云物理及人工影響天氣研究進(jìn)展

1 人工影響天氣重大工程進(jìn)展

1.1 東北區(qū)域人影工程

2架新舟60增雨飛機(jī)通過系統(tǒng)驗(yàn)收。新舟60 增雨飛機(jī)具備冷暖云及多云型催化能力、云宏觀實(shí)時探測能力、空地通信能力，可承擔(dān)精準(zhǔn)催化播撒、科學(xué)研究、人影作業(yè)效果評估等各項(xiàng)業(yè)務(wù)和科研任務(wù)；系統(tǒng)集成化、自動化程度高。

空中國王增雨飛機(jī)完成改裝及定檢后入關(guān)落地河北。在美國完成民用航空器改裝設(shè)計批準(zhǔn)（MDA）檢查和補(bǔ)充型號適航證（STC）檢查并獲得美國STC證，12月初裸機(jī)及全部機(jī)載設(shè)備先后入關(guān)，獲得中國民航總局頒發(fā)的國籍證。

成功舉辦3期培訓(xùn)班，150余名來自東北區(qū)域人影作業(yè)一線技術(shù)人員接受培訓(xùn)?！叭擞帮w機(jī)作業(yè)及地面作業(yè)指揮培訓(xùn)班”重點(diǎn)面向省級人影飛機(jī)作業(yè)技術(shù)骨干，圍繞機(jī)載探測儀器及操作、增雨催化作業(yè)技術(shù)、飛機(jī)資料質(zhì)量控制及分析等內(nèi)容培訓(xùn)?！叭擞帮w機(jī)運(yùn)行管理與機(jī)上觀測及增雨作業(yè)技術(shù)培訓(xùn)班”重點(diǎn)面向地市（盟）、縣級人影業(yè)務(wù)人員，結(jié)合人影5段式業(yè)務(wù)、1平臺4系統(tǒng)進(jìn)行實(shí)際操作培訓(xùn)。

成功舉辦“東北區(qū)域人工影響天氣能力建設(shè)工程檢查總結(jié)會”。向國家發(fā)改委領(lǐng)導(dǎo)和中國氣象局領(lǐng)導(dǎo)匯報了項(xiàng)目的總體進(jìn)展和東北區(qū)域人影基本能力的提升情況。

全面啟動驗(yàn)收工作。印發(fā)了《東北區(qū)域人工影響天氣能力建設(shè)項(xiàng)目驗(yàn)收工作方案》。先后完成新舟60增雨飛機(jī)系統(tǒng)驗(yàn)收，作業(yè)指揮應(yīng)用系統(tǒng)的合同驗(yàn)收。（裝備研發(fā)與保障室，作業(yè)指揮與運(yùn)行中心）

1.2 西北區(qū)域人影工程

完成西北區(qū)域人影項(xiàng)目初步設(shè)計，已獲國家發(fā)改委批復(fù)；啟動西北區(qū)域人影項(xiàng)目建設(shè)，制定西北區(qū)域人影能力建設(shè)2017年度建設(shè)實(shí)施方案；完成西北區(qū)域人影項(xiàng)目管理辦公室的組建和人員的落實(shí)，制定相關(guān)管理辦法并開始執(zhí)行。（區(qū)域中心管理辦公室）

1.3 其他區(qū)域人影工程

完成中部區(qū)域人影項(xiàng)目可行性研究報告，上報國家發(fā)改委并由國家發(fā)改委組織完成了評估工作，目前正按照評估意見組織修改；積極推進(jìn)華北、西南和東南區(qū)域人影可研報告的編制，完成1次技術(shù)審查，正在按審查意見組織修改。（區(qū)域中心管理辦公室）

2 科學(xué)研究進(jìn)展

2.1 云水資源評估與利用示范

提出和完善了云水資源概念及評估理論和方法，優(yōu)化建立了中國不同區(qū)域三維云場、云水場診斷技術(shù)；完成2000年以來中國云水資源觀測診斷評估，并利用衛(wèi)星、飛機(jī)和地基觀測資料對關(guān)鍵參量和評估結(jié)果進(jìn)行檢驗(yàn)。設(shè)計開發(fā)了云水資源評估及其開發(fā)效果預(yù)估數(shù)值模式，實(shí)現(xiàn)典型云降水過程的似真模擬和區(qū)域云水資源數(shù)值精細(xì)評估。提出了云水資源利用對區(qū)域水資源影響的定量評估模型，得到云水資源利用對區(qū)域水資源供需影響的初步模擬成果。開展了南水北調(diào)中線丹江口水源地示范區(qū)和超大城市供水北京兩庫水源地兩類固定目標(biāo)區(qū)人工增雨作業(yè)關(guān)鍵技術(shù)的研究和作業(yè)實(shí)施，獲得大量觀測和催化作業(yè)的科學(xué)數(shù)據(jù)，在固定目標(biāo)區(qū)云水資源開發(fā)效果的數(shù)值模擬評估和多參量物理檢驗(yàn)監(jiān)測評估等方面取得進(jìn)展。（作業(yè)指揮與運(yùn)行中心）

2.2 FY-4靜止衛(wèi)星云產(chǎn)品的云物理開發(fā)及人影應(yīng)用示范

開展了基于FY-4A衛(wèi)星、地面和探空觀測的云底高度等云宏觀參量研發(fā)，并與地基激光雷達(dá)觀測云底高度進(jìn)行對比檢驗(yàn)；開展了基于FY-4A衛(wèi)星觀測的云檢測、過冷水和云相態(tài)識別算法研發(fā)，并與飛機(jī)直接觀測以及與H8和MODIS衛(wèi)星等同類產(chǎn)品進(jìn)行對比檢驗(yàn)；開展了基于FY-4A衛(wèi)星多通道觀測閾值法的人影作業(yè)目標(biāo)云分類識別算法研發(fā)，探索作業(yè)條件監(jiān)測方法；升級FY-4A衛(wèi)星人影云結(jié)構(gòu)宏、微觀反演產(chǎn)品與云降水精細(xì)分析系統(tǒng)（CPAS）；利用飛機(jī)、衛(wèi)星和多種地基觀測，初步開展了FY-4衛(wèi)星云宏、微觀物理參數(shù)產(chǎn)品空地聯(lián)合觀測檢驗(yàn)，在天津全運(yùn)會服務(wù)中得到初步應(yīng)用；同時開展了FY-4A衛(wèi)星產(chǎn)品在人影5段業(yè)務(wù)中的應(yīng)用示范研究。（作業(yè)指揮與運(yùn)行中心）

2.3 人工增雨隨機(jī)化外場試驗(yàn)和效果檢驗(yàn)技術(shù)

2017年在4個省試驗(yàn)區(qū)繼續(xù)開展隨機(jī)化人工增雨外場試驗(yàn)，共獲取地面火箭增雨作業(yè)隨機(jī)試驗(yàn)樣本43個、飛機(jī)增雨作業(yè)隨機(jī)試驗(yàn)樣本2個。外場試驗(yàn)期間，及時收集相關(guān)的衛(wèi)星、雷達(dá)、探空、地面雨滴譜和地面降雨量等云降水探測資料及人工增雨作業(yè)資料，補(bǔ)充完善了樣本數(shù)據(jù)庫。對2017年外場試驗(yàn)的一些個例進(jìn)行了初步分析研究。山東、福建、吉林3省分別完善了適合本地的基于地面降水量的人工增雨作業(yè)效果統(tǒng)計檢驗(yàn)技術(shù)方法及相應(yīng)的軟件；福建、海南兩省分別完善了適合本地的基于雷達(dá)探測的人工增雨作業(yè)效果物理檢驗(yàn)技術(shù)方法及相應(yīng)的軟件。（作業(yè)指揮與運(yùn)行中心）

2.4 南方大范圍云系人工增雨作業(yè)潛力與作業(yè)技術(shù)

結(jié)合微波輻射計建立了江西省秋冬季雷達(dá)回波與云雨滴有效直徑統(tǒng)計反演關(guān)系，進(jìn)一步完善了FY-2和葵花靜止衛(wèi)星云微物理反演系統(tǒng)，建立了過冷層狀云人工增雨作業(yè)衛(wèi)星指標(biāo)，開展FY-4高分辨靜止衛(wèi)星云微物理反演系統(tǒng)的研發(fā)，在四川宜賓開展云物理外場探測試驗(yàn)。（區(qū)域中心管理辦公室）

2.5 基于功效分析的非隨機(jī)化人工增雨作業(yè)效果檢驗(yàn)最優(yōu)實(shí)用統(tǒng)計方案

2017年開展了江西省2008—2014年冬季飛機(jī)增雨作業(yè)對季節(jié)降水量的影響及其范圍的研究。根據(jù)7年冬季71次飛機(jī)增雨作業(yè)期間的平均風(fēng)向，選取目標(biāo)區(qū)9個站點(diǎn)和下風(fēng)方12個站點(diǎn)作為研究對象，并在上風(fēng)方選取5個冬季歷史平均降水量相關(guān)系數(shù)和這21個站點(diǎn)中最高的站點(diǎn)作為對比站點(diǎn)，分別建立目標(biāo)區(qū)9個站點(diǎn)和下游區(qū)12個站點(diǎn)與5個對比站點(diǎn)之間的歷史回歸方程，利用區(qū)域歷史回歸技術(shù)方法分析研究目標(biāo)區(qū)及其下游區(qū)的增雨效果。分析顯示，目標(biāo)區(qū)平均增雨17.30%（t檢驗(yàn)的顯著性水平p=0.25），下游區(qū)平均增雨21.67%（t檢驗(yàn)的顯著性水平p=0.0013），表明江西省冬季增雨作業(yè)的影響范圍不僅僅局限于目標(biāo)區(qū)，還影響到距離目標(biāo)區(qū)126 km的下游地區(qū)。（作業(yè)指揮與運(yùn)行中心）

2.6 2017年春季北京自然冰核觀測及初步分析

2017年3月20日至4月19日利用5L畢格混合云室進(jìn)行北京春季大氣自然冰核觀測，觀測時間分別在09∶00和14∶00，每天觀測2次，每次時長約2 h。觀測的方法、時間以及位置與1963、1995、1996年的觀測基本一致。觀測的活化溫度為-10 ℃、-15 ℃、 -20 ℃、 -25 ℃、 -30 ℃ 5個溫度點(diǎn)。本次觀測結(jié)果表明，不同活化溫度點(diǎn)下的冰核粒子濃度逐日變化有著較好的一致性，這與1963、1995、1996年的觀測結(jié)果一致。此次觀測的冰核粒子濃度總體上比1963年的觀測結(jié)果要高，但明顯低于1995與1996年的觀測結(jié)果，從此次試驗(yàn)結(jié)果來看，過去20年的自然變化和人為活動并沒有使得冰核粒子濃度明顯增加。觀測期間于3月20—25日有間斷性的弱降水，而冰核粒子濃度在降水過程中有明顯減小的趨勢，這表明降水對冰核有消除的作用。冰核觀測過程中能見度儀也進(jìn)行了同步觀測，對比冰核粒子濃度和能見度的逐日變化可以看出二者呈明顯的反相關(guān)，-25 ℃的冰核粒子濃度與能見度的相關(guān)系數(shù)為-0.51。觀測期間發(fā)生過多次霧霾天氣，而在無降水天氣情況下，能見度受到霧霾嚴(yán)重程度的直接影響。同時將冰核粒子濃度與其他氣象要素進(jìn)行比較，可以看到冰核粒子濃度與風(fēng)速呈反相關(guān)，而與相對濕度呈弱正相關(guān)，這表明擴(kuò)散條件越好，冰核粒子越少。有人提出的冰核粒子濃度與氣壓呈明顯反相關(guān)，在此次試驗(yàn)中并沒有明顯的體現(xiàn)。（裝備研發(fā)與保障室）

2.7 青藏高原云降水物理過程研究

利用2014年7月1日至8月31日期間在西藏那曲的地面觀測數(shù)據(jù)，結(jié)合FY-2E衛(wèi)星的TBB資料，分析研究了青藏高原夏季（7—8月）對流云及其降水過程和雨滴譜分布特征。研究結(jié)果表明，觀測試驗(yàn)期間青藏高原對流活動主要集中在高原東南部和中部地區(qū)，其降水過程存在準(zhǔn)2周的周期性；由于高原的加熱效應(yīng)，對流云和降水過程有著顯著的日變化特征，對流活動在11∶00(當(dāng)?shù)貢r間)由局地?zé)釋α靼l(fā)展，經(jīng)合并增長在17∶00—18∶00達(dá)到最強(qiáng)，入夜后降水過程開始偏平流性并持續(xù)至06∶00，之后逐漸消散，上午對流活動較少。高原對流云平均云頂海拔高度為11.5 km左右，最大云頂高可超過19 km；平均云底高度6.88 km。降水過程主要表現(xiàn)為短時陣性降水，持續(xù)時間基本小于1 h，平均降水強(qiáng)度在1.2 mm/h左右。 另外，研究發(fā)現(xiàn)高原雨滴譜分布相對于同緯度和季節(jié)的平原地區(qū)較寬，導(dǎo)致高原對流易產(chǎn)生降水。Γ分布相對于M-P分布更適用于對高原上的雨滴譜分布進(jìn)行擬合。

利用TRMM、CloudSat和Aqua多源衛(wèi)星觀測資料和地基垂直指向雷達(dá)資料，對第3次青藏高原試驗(yàn)期間2014年7月9日13∶00—16∶00 BST發(fā)生在那曲地區(qū)的一次深對流云的垂直結(jié)構(gòu)特征進(jìn)行了分析，發(fā)現(xiàn)深對流云在零度層以下雷達(dá)反射率因子遞增非?？?，表明對流云內(nèi)固態(tài)降水粒子下落至零度層以下后融化過程有很重要的作用；在對流減弱階段有明顯的零度層亮帶出現(xiàn)；深對流云主要為冰相云，云內(nèi)10 km以上主要是豐富小冰粒子，而10 km以下是較少的大冰晶粒子；深對流云的微物理過程都主要包括混合相過程和冰化過程（圖1）。（開放實(shí)驗(yàn)室）

2.8 北京持續(xù)性霾和霧霾混合天氣PM2.5濃度、能見度與大氣邊界層高度相互作用關(guān)系

利用2014年1月至2015年3月期間氣科院云霧物理環(huán)境開放實(shí)驗(yàn)室在北京獲取的霧霾地面觀測資料（包括顆粒物儀、能見度儀、激光雷達(dá)、云高儀和輻射計等觀測資料），研究北京持續(xù)性霾和霧霾混合天氣PM2.5濃度、能見度與大氣邊界層高度的相互作用關(guān)系，并通過典型霾和霧霾混合天氣個例探討了顆粒物濃度與大氣邊界層相互作用的物理機(jī)制。研究結(jié)果表明，在霾和霧霾混合過程中隨著PM2.5濃度增加，能見度呈指數(shù)遞減。由于霧滴的生成， 相同的PM2.5濃度，霧霾混合過程比霾過程中能見度更低；PM2.5濃度和大氣邊界層高度呈反相關(guān)關(guān)系；能見度和大氣邊界層高度呈正相關(guān)關(guān)系。通過持續(xù)性霧霾個例分析發(fā)現(xiàn)，邊界層內(nèi)雙層逆溫結(jié)構(gòu)的出現(xiàn)和維持對持續(xù)性霾和霧霾混合天氣的生成起了重要作用。由于西南暖濕氣流的作用，上層逆溫形成，使得地面PM2.5濃度不斷累積增加；夜間地面輻射冷卻形成下層逆溫，大氣中顆粒物存在使到達(dá)地面的太陽輻射減少，白天下層逆溫得以維持。污染過程中雙層逆溫的變化與顆粒物和輻射相互作用過程密切相關(guān)。當(dāng)污染物逐漸累加 (PM2.5＞150～200μg/m3)，近地面散射輻射加強(qiáng)，輻射冷卻引起上面逆溫層的下降導(dǎo)致下層逆溫更加穩(wěn)定，大氣邊界層高度下降，地面污染進(jìn)一步加劇。上層逆溫的形成以及隨后的下降過程是形成北京持續(xù)性霧霾天氣的重要因素。這種正反饋機(jī)制在霧霾混合天氣條件下更強(qiáng)烈（圖2）。(開放實(shí)驗(yàn)室）

2.9 云室研制和催化劑研發(fā)

完成修繕購置項(xiàng)目暖云室結(jié)構(gòu)系統(tǒng)、性能參數(shù)監(jiān)測系統(tǒng)的設(shè)計，開展初步原理測試試驗(yàn)。完成了主體云室部分、檢測儀器和輔助系統(tǒng)、狀態(tài)控制、電器控制機(jī)柜和顯示控制部分的設(shè)計和搭建。完成行業(yè)專項(xiàng)課題檢測云室的建設(shè)任務(wù),目前已運(yùn)送到北京并安裝，準(zhǔn)備綜合調(diào)試。開展了暖云催化劑實(shí)驗(yàn)室播撒模擬試驗(yàn)，新型吸濕性催化劑初步試驗(yàn)表明，它有一定的影響暖性云霧的能力，配方在進(jìn)一步改進(jìn)中（圖3）。（開放實(shí)驗(yàn)室，裝備研發(fā)與保障室）

3 科研成果及其推廣應(yīng)用

3.1 云降水顯式預(yù)報系統(tǒng)業(yè)務(wù)化運(yùn)行

云降水顯式預(yù)報系統(tǒng)（Cloud Precipitation Explicit Forecast System, CPEFS_V1.0）于2017年7月28日正式業(yè)務(wù)運(yùn)行，該預(yù)報系統(tǒng)將全國（大陸）分為8個區(qū)域，1天2次實(shí)時發(fā)布預(yù)報產(chǎn)品31種，時間分辨率1 h，空間分辨率3 km。相比2013版人影模式預(yù)報系統(tǒng)，增加了5種預(yù)報產(chǎn)品（云底高度、云底溫度、雷達(dá)回波、云量、相對濕度）。實(shí)現(xiàn)了可適應(yīng)不同目標(biāo)復(fù)雜云系的人影專項(xiàng)預(yù)報業(yè)務(wù)服務(wù)，通過對云結(jié)構(gòu)和人影作業(yè)條件的預(yù)報，可有效提出作業(yè)潛力區(qū)和催化作業(yè)預(yù)案的建議，取得較好的服務(wù)效果。（作業(yè)指揮與運(yùn)行中心）

3.2 催化模擬技術(shù)及作業(yè)效果數(shù)值模擬評估

在CAMS云物理方案的冷云催化模塊中實(shí)現(xiàn)了實(shí)際飛行航線上的催化和火箭催化的似真模擬功能，探索開展了多機(jī)催化作業(yè)效果的模擬評估，以及夏季對流云火箭催化效果的模擬評估等。（作業(yè)指揮與運(yùn)行中心）

3.3 過冷水的飛機(jī)和遙感觀測識別方法和應(yīng)用

利用DMT和PMS飛機(jī)云物理探測資料，提出了飛機(jī)探測粒子譜結(jié)合二維圖像聯(lián)合識別過冷水的方法；通過大量個例研究，給出了過冷水區(qū)和冰云區(qū)的衛(wèi)星觀測云特征，探索建立利用RGB 3色合成圖像結(jié)合T-Re結(jié)構(gòu)特征和云參數(shù)譜分布的過冷水的衛(wèi)星監(jiān)測識別方法；通過飛機(jī)資料與雷達(dá)觀測的時空匹配，統(tǒng)計研究了過冷水雷達(dá)觀測特征，提出了雷達(dá)回波頂溫、回波強(qiáng)度和回波梯度聯(lián)合識別過冷水區(qū)的方法，并形成分析軟件，不僅為人影作業(yè)條件識別提供支撐，同時為開展飛機(jī)積冰監(jiān)測預(yù)報服務(wù)提供技術(shù)支持（作業(yè)指揮與運(yùn)行中心）

3.4 不同云系催化作業(yè)效果檢驗(yàn)方法

根據(jù)業(yè)務(wù)需求，探索不同云系不同作業(yè)方式效果檢驗(yàn)的合理方案，提出檢驗(yàn)方法，建立業(yè)務(wù)流程。提出基于作業(yè)方式和劑量的作業(yè)合理性判別方法。綜合選取對比單元或?qū)Ρ葏^(qū)，結(jié)合雷達(dá)、衛(wèi)星和降水等觀測資料，分析播云后的作業(yè)效果。提出針對均勻?qū)訝钤频亩鄥?shù)區(qū)域動態(tài)對比檢驗(yàn)方法和針對對流云的雷達(dá)回波單體追蹤識別方法。上述2種方法已在多次重大活動人影服務(wù)中得到應(yīng)用。（作業(yè)指揮與運(yùn)行中心）

3.5 云降水精細(xì)分析系統(tǒng)（CPAS）的發(fā)展

云降水精細(xì)處理分析系統(tǒng)（CPAS）是基于云物理分析技術(shù)和AuroView地理信息及圖形圖像和計算機(jī)技術(shù)等研發(fā)的一套氣象專業(yè)系統(tǒng)。系統(tǒng)具備多尺度云降水物理的精細(xì)監(jiān)測和預(yù)報分析功能，圍繞云降水生消演變精細(xì)結(jié)構(gòu)特征，實(shí)現(xiàn)對多源、多類監(jiān)測信息（衛(wèi)星、雷達(dá)、探空、雨量、飛機(jī)微物理等）的加工處理、計算分析、反演融合等云結(jié)構(gòu)實(shí)時綜合分析及追蹤識別等功能；具有對多尺度動力和云數(shù)值模式預(yù)報產(chǎn)品的處理分析功能。在此基礎(chǔ)上，面向不同業(yè)務(wù)實(shí)現(xiàn)飛機(jī)和地面人工增雨、防雹等作業(yè)條件預(yù)報分析、監(jiān)測識別、作業(yè)設(shè)計、跟蹤指揮和效果分析等人影業(yè)務(wù)功能。系統(tǒng)還具有降水相態(tài)識別、飛機(jī)積冰分析以及暴雨冰雹等強(qiáng)對流識別等功能，可實(shí)現(xiàn)各類專題產(chǎn)品制作。為適應(yīng)科研和業(yè)務(wù)不同需求，分科研版和業(yè)務(wù)版分類發(fā)展特色功能，目前已發(fā)展有CPAS2.0、CPAS-WMC和CPAS-NE等系列版本，2017年獲得多項(xiàng)軟件著作權(quán)。在人影3年行動計劃的推動下，已在全國20多個省級單位400多個市縣得到移植應(yīng)用，基于多項(xiàng)科研項(xiàng)目及業(yè)務(wù)和工程項(xiàng)目的支撐，該系統(tǒng)核心技術(shù)不斷發(fā)展，在我國人影日常和各類重大服務(wù)中發(fā)揮著重要作用（作業(yè)指揮與運(yùn)行中心）。

3.6 東北區(qū)域人影綜合業(yè)務(wù)

2017年完成東北區(qū)域人影綜合業(yè)務(wù)系統(tǒng)的驗(yàn)收。由“1平臺4系統(tǒng)”構(gòu)成的系統(tǒng)使東北區(qū)域?qū)崿F(xiàn)了3方面技術(shù)的進(jìn)步：建立了適應(yīng)區(qū)域、省、市、縣業(yè)務(wù)需求功能匹配的一體化業(yè)務(wù)平臺（CPAS-NE），完整支撐各級人影5段業(yè)務(wù)。各級人影數(shù)據(jù)實(shí)現(xiàn)規(guī)范化集中存儲；區(qū)域、省、市縣、直至作業(yè)點(diǎn)的各級信息（指令）傳遞通道實(shí)現(xiàn)，使得 “指令下得去，信息上得來，數(shù)據(jù)存得住”?！?平臺4系統(tǒng)”為核心的東北區(qū)域人影業(yè)務(wù)系統(tǒng)構(gòu)架具有功能高內(nèi)聚和系統(tǒng)間低耦合特性，可以靈活拆卸拼裝部署。軟件及其結(jié)構(gòu)作為業(yè)務(wù)系統(tǒng)范例，寫入《人工影響天氣綜合業(yè)務(wù)系統(tǒng)建設(shè)指南》，向全國推廣。（作業(yè)指揮與運(yùn)行中心）

4 重大科學(xué)試驗(yàn)

4.1 基于高性能人影飛機(jī)的大型外場飛機(jī)試驗(yàn)

2017年3—4月，針對即將在湖北宜昌開展的飛機(jī)試驗(yàn)，提出湖北飛行區(qū)域建議，并完成了湖北西南低渦7架次的探測飛行。2017年8—10月，首次利用我國高性能飛機(jī)開展臺風(fēng)外圍云系探測，并通過海事衛(wèi)星實(shí)現(xiàn)了空地聯(lián)合實(shí)時指揮。探測試驗(yàn)歷時近1個月，期間共飛行6架次，獲取了包括氣溶膠、云微物理特征等探測資料，初步分析了氣溶膠垂直特征及南方淺積云微物理特性。6個飛行個例獲取了深圳上空低層的12條氣溶膠垂直探測廓線。初步分析結(jié)果表明深圳地面氣溶膠數(shù)濃度在不同天氣條件下變化范圍較大，為500～9000個/cm3，氣溶膠譜在邊界層以內(nèi)垂直方向上變化不大，主要為雙峰或3峰分布。穿云探測在6 km左右觀測到冰相粒子，穿云最低溫度為-6 ℃，有板狀、針狀冰晶出現(xiàn)（圖4）。（開放實(shí)驗(yàn)室，飛機(jī)運(yùn)行中心）

4.2 廬山云霧外場觀測

2015年11月江西廬山云霧試驗(yàn)站恢復(fù)建設(shè)，架設(shè)了現(xiàn)代觀測儀器的試驗(yàn)平臺。利用廬山云霧試驗(yàn)站包括能見度儀、雨滴譜儀、云高儀、微雨雷達(dá)、霧滴譜儀以及自動氣象站的云霧觀測平臺，開展了2017年云霧降水過程觀測，并獲取大量云霧觀測資料和降水、凍雨、降雪、梅雨、暴雨等不同降水過程個例。通過對2015年秋冬季廬山云霧和云內(nèi)降水的統(tǒng)計分析可知， 云霧滴譜呈雙峰型，峰值粒徑分別為6 μm和12～15 μm，2個粒徑峰值濃度均達(dá)到了10 μm-1cm-3量級以上，最大可達(dá)到93 μm-1cm-3。廬山云霧滴譜較寬，粒徑可達(dá)到毛毛雨級別。云內(nèi)降水以小雨級別為主，隨著降雨級別的增加，雨滴譜越寬，云霧滴譜越窄，云內(nèi)存在明顯的碰并過程。廬山海拔較高，降水云系被動接地是云霧降水長時間持續(xù)的主要原因，云內(nèi)降水過后水汽條件豐富，盛行北風(fēng)，平均風(fēng)速在2.9～4.5 m/s，易形成蒸發(fā)霧（圖5）。（開放實(shí)驗(yàn)室，裝備研發(fā)與保障室）

5 業(yè)務(wù)與服務(wù)

5.1 人影作業(yè)指揮業(yè)務(wù)

面向全國每日發(fā)布7類衛(wèi)星云特征參量監(jiān)測反演產(chǎn)品和3個模式系統(tǒng)運(yùn)行的20種模式預(yù)報產(chǎn)品，實(shí)時收集全國飛機(jī)和地面作業(yè)信息。每周制作《未來一周人影作業(yè)需求分析》和《全國人影作業(yè)信息報》；每月制作《全國人影作業(yè)信息上報質(zhì)量報》；每季度編制完成《全國人工影響天氣工作動態(tài)》。依托不斷發(fā)展的云降水精細(xì)預(yù)報系統(tǒng)和監(jiān)測識別分析、作業(yè)設(shè)計及指揮能力的提高,為華北、東北干旱，呼倫貝爾畢拉河、烏瑪林火，建軍90周年閱兵、內(nèi)蒙古成立70周年大慶紀(jì)念活動保障，第13屆天津全運(yùn)會人影保障服務(wù)等，制作完成41期《人影作業(yè)條件潛勢預(yù)報》，組織專題會商25次，制作6期《監(jiān)測預(yù)警報》，5期《飛機(jī)作業(yè)方案指導(dǎo)報》，2期《全國飛機(jī)作業(yè)方案設(shè)計質(zhì)量報》，外場共計飛行作業(yè)10架次，取得良好的服務(wù)效果。圓滿完成內(nèi)蒙古大興安嶺畢拉河“5·2”森林火災(zāi)和秦皇島4月25日森林火區(qū)滅火等國家重大災(zāi)害應(yīng)急任務(wù)。 CPEFS_V1.0業(yè)務(wù)模式，具有3 km水平分辨率，可提前24 h分析預(yù)報擬作業(yè)云系及其中對流單體的移向移速，云系的垂直結(jié)構(gòu)特征及降水機(jī)制。如在內(nèi)蒙古成立70周年大慶人影保障服務(wù)中，根據(jù)預(yù)報提前24 h在西北部防區(qū)增加移動火箭作業(yè)裝備，為大慶活動消減雨作業(yè)發(fā)揮重要作用。在呼倫貝爾畢拉河森林滅火應(yīng)急服務(wù)中，針對固定的林火目標(biāo)區(qū)，根據(jù)新舟60飛機(jī)特性，設(shè)計充分播撒催化作業(yè)方案，確保催化作業(yè)后催化劑擴(kuò)散影響范圍長時段位于畢拉河林火區(qū)域，實(shí)現(xiàn)固定目標(biāo)區(qū)最佳增雨作業(yè)。作業(yè)之后火場地區(qū)24 h累積降水達(dá)39.2 mm，而其余地區(qū)一般為小到中雨，增雨效果明顯，受到國家森林防火指揮部、內(nèi)蒙古區(qū)黨委和政府的感謝和表揚(yáng)（圖6）。（作業(yè)指揮與運(yùn)行中心，飛機(jī)運(yùn)行中心）

5.2 人影飛機(jī)運(yùn)行業(yè)務(wù)

（1）東北區(qū)域和其他抗旱省級抗旱服務(wù)。認(rèn)真組織做好國家級增雨飛機(jī)在東北4省區(qū)重點(diǎn)作業(yè)區(qū)的抗旱減災(zāi)、河庫增蓄、生態(tài)環(huán)境保護(hù)、森林草原防火等作業(yè)服務(wù)。春夏期間，根據(jù)抗旱增蓄及降低森林草原火險等級需要，2架增雨飛機(jī)B-3435和B-3726分別以長春龍嘉機(jī)場和沈陽桃仙機(jī)場為主降基地，適時轉(zhuǎn)場黑龍江加格達(dá)奇地區(qū)和內(nèi)蒙古呼倫貝爾市開展抗旱增蓄作業(yè)服務(wù)。根據(jù)中原地區(qū)春、秋、冬季及新疆和田地區(qū)冬季抗旱及常態(tài)化作業(yè)需求，B-3726增雨飛機(jī)分別以河南省新鄭國際機(jī)場和新疆自治區(qū)和田機(jī)場為基地，聯(lián)合河南省及新疆自治區(qū)人影部門開展輻射周邊省市的飛機(jī)增雨作業(yè)服務(wù)。（飛機(jī)運(yùn)行中心）

（2）科技成果轉(zhuǎn)化及對外交流。聯(lián)合中國華云氣象科技集團(tuán)公司在昌平中國氣象科技園成立人影機(jī)載大氣探測實(shí)驗(yàn)室，搭建開放式人影機(jī)載探測設(shè)備保障、科研開發(fā)與應(yīng)用平臺，開展儀器設(shè)備研發(fā)應(yīng)用、技術(shù)創(chuàng)新、成果轉(zhuǎn)化、技術(shù)咨詢等，為人影飛機(jī)平臺和機(jī)載云物理探測儀器的可靠運(yùn)行提供有力保障。推進(jìn)中國氣象局小型業(yè)務(wù)項(xiàng)目“人工影響天氣作業(yè)裝備彈藥全程監(jiān)控應(yīng)用示范”、中國氣象科學(xué)研究院基本科研業(yè)務(wù)費(fèi)專項(xiàng)“示蹤法在人工增雨（雪）效果評估中的應(yīng)用”等業(yè)務(wù)與科研項(xiàng)目的研究。組織氣象行業(yè)標(biāo)準(zhǔn)項(xiàng)目《人工影響天氣作業(yè)裝備與彈藥標(biāo)識編碼技術(shù)規(guī)范》編寫和“人工影響天氣裝備彈藥監(jiān)控管理系統(tǒng)” 建設(shè)及全國范圍推廣建設(shè)工作。加強(qiáng)對外交流與協(xié)作，積極參加高校和科研院所專家關(guān)于氣溶膠、云和降水物理講座的學(xué)習(xí)與研討，多人次赴美參加機(jī)載云粒子探測儀器和激光雷達(dá)等機(jī)載遙感設(shè)備的使用與維護(hù)培訓(xùn)，并聯(lián)合美國DMT公司在國內(nèi)開展機(jī)載探測設(shè)備應(yīng)用聯(lián)合培訓(xùn)和技術(shù)交流，加強(qiáng)青年科技人才培養(yǎng)和國家飛機(jī)運(yùn)行管理專業(yè)隊伍的建設(shè)。（飛機(jī)運(yùn)行中心）

（3）探測設(shè)備維護(hù)及飛機(jī)運(yùn)維。按照機(jī)載探測設(shè)備使用與標(biāo)定要求，完成對DMT粒子測量系統(tǒng)定期檢測與標(biāo)定，組織實(shí)施2架新舟60增雨飛機(jī)12M（宜昌）、18M（洛陽）和24M（閻良）的定檢維修，并開展了空中國王、新舟60增雨飛機(jī)托管招標(biāo)工作。（飛機(jī)運(yùn)行中心）

圖1 112次降水的平均雨滴譜和總平均雨滴譜(a)，平均雨滴譜、M-P分布雨滴譜以及擬合的Γ分布雨滴譜(b)Fig.1 Raindrop size distribution: (a) Mean raindrop size distribution of 112 rainfall events and totally mean raindrop size distribution; (b) Mean raindrop size distribution, M-P raindrop size distribution and Γ raindrop size distribution

圖2 北京霾過程中云高儀CL31后向散射信號(a)、微脈沖激光雷達(dá)歸一化相對后向散射信號的時間高度剖面(b)，以及PM2.5濃度和微脈沖激光雷達(dá)反演的邊界層高度隨時間的演變(c)Fig.2 Time-height cross sections of (a) the backscatter density detected by the CL31, (b) the NRB detected by the MPL, and (c)the temporal evolution of PM2.5 mass concentration and PBL height retrieved by the NRB of MPL during the entire haze event in Beijing

圖3 新建暖云室結(jié)構(gòu)示意Fig.3 The structural diagram of our new warm-cloud chamber

圖4 2017年9月飛機(jī)觀測的深圳氣溶膠垂直廓線Fig.4 Vertical profiles of aerosol observed over Shenzhen, Guangdong Province

圖5 冬季廬山云霧個例的霧滴譜（散點(diǎn)）及平均滴譜（曲線）分布Fig.5 The size distribution of fog droplet number (scatter) and their mean distribution (curve) of cloud and fog cases during autumn and winter over the Lushan Mountains

圖6 2017年5月5日B-3435增雨作業(yè)飛機(jī)預(yù)設(shè)航線及擴(kuò)散60、90、120 min的影響區(qū)域示意Fig.6 The B-3435 aircraft seeding fl ight plan (left), and the spread regions after 60, 90, and 120 minutes (right) on May 5, 2017

Progress in Cloud Physics and Weather Modification

1 Major weather modification projects

1.1 Weather modification project in Northeast China

Precipitation-Enhancement Systems on 2 Xinzhou 60 aircrafts passed inspection.The aircrafts are capable of catalyzing cold and warm clouds, real-time macroscopic cloud detection and ground-air communication;undertaking precise catalyzing and seeding operations, and scientific research; and evaluating weather modification operation, and the other related tasks, with high degree of system integration and automation.

The King Air aircraft has been re-f i tted, inspected and settled in Hebei. Completed the US’ inspections of MDA and STC, with an STC certificate.In early December, the empty aircraft and all the airborne equipment passed the custom’s inspection with a nationality certificate issued by CAAC.

Held 3 training sessions with more than 150 weather modification operational technicians from Northeast China.The “Weather Modification Aircraft Operations and Ground Operations Directing” session mainly aims to training the key weather modification aircraft operationists at the provincial level on the airborne detection instruments operations, rainfall enhancement seeding operations, aircraft data quality control and analysis,and etc.The “Weather Modification Aircraft Operations Management and Onboard Observation and Rainfall Enhancement Operations” session mainly aims to training the weather modification operation personals at the city (league) and county level on the real-time operations that integrate 5-step operations, a platform and 4 systems of weather modification.

Held a project-inspection summary workshop in order to build up the regional weather modification capability in Northeast China.The related project progress and the improved weather modification capability in Northeast China have been reported to the leaders of NDRC and CMA.

All inspection operations have started.The Proposed Weather Modification Project in Northeast China has been released.Both the Xinzhou 60 precipitation enhancement aircraft and the ground operation directing application system have passed inspections.(Equipment R&D and Support Division, Operation Commanding and Running Centre)

1.2 Development of weather modification projects in Northwest China

Completed preliminary design of a Weather Modification Project in Northwest China that was later approved by the NDRC, and activated in operation with the 2017 project implementation plan in place.Established a regional weather modification administrative office with appropriate personnel in Northwest China.Developed and then carried out the relevant administrative measures.(Regional Centre Administration Office)

1.3 Weather modification projects in other regions

Completed and submitted “the Feasibility Study Report (FSR) of Weather Modification Project in Central China” to the NDRC for evaluation.The FSR has now been modified in response to the evaluation comments.Similar FSRs for Weather Modification Projects in North, Southwest and Southeast China are in progress.One technical review has been carried out and the relevant updates are on going based on the review comments.(Regional Centre Administration Office)

2 Progress in scientific research

2.1 Assessing cloud-water resources and their utilizing demonstration

We have put forward and improved the concept of using cloud-water resources, and assessing theory and methodologies.Optimized the diagnosis of three-dimensional cloud and cloud-water field in different regions of China, and completed the diagnosis of cloud-water resources from observations obtained since 2000.Validated some key parameters and diagnosed results against satellite, aircraft and ground-based observations.Meanwhile, we designed and developed numerical models for cloud-water resource assessment and impact estimate, which are capable of simulating cloud precipitation process and evaluating regional cloud-water resources.Additionally, we proposed a quantitative evaluation model for the impact of cloud water resources on regional water resources, and obtained preliminary results of utilizing cloud-water resources on regional water resource supply and demand.In practical, we carried out the studies of key technologies and operations of conducting artificial rain enhancement in two types of fixed target areas: one at Danjiangkou that is a water source demonstration site at the middle portion of the South-to-North Water Diversion, and another in Beijing where two reservoirs are located.Therefore, abundant scientific data of observations and cloud catalytic operations were obtained, with significant progress made in both the numerical simulations of cloud-water resources over the fixed target areas and the evaluation of multi-parameter physical inspection and assessment.(Operation Commanding and Running Centre)

2.2 Analysis of cloud physics products and demonstration of weather modification application both with FY-4 stationary satellite

Macroscopic cloud parameters are retrieved from FY-4A satellite, ground and rawinsonde observations,with the cloud base height validated against ground-based lidar observations.Algorithms of detecting clouds and distinguishing supercooled water from cloud phase from FY-4A satellite are developed, and the products so retrieved are compared with the same products from H8 and MODIS satellites and in-situ aircraft observations.Based on FY-4A multi-channel observation thresholds, we developed an algorithm to classify target clouds of weather modification operation and explored the associated monitoring in an operational setting.Upgraded the FY-4A satellite retrieval products of both the macroscopic and microscopic cloud structures and Cloud Precipitation Analysis System (CPAS).Using aircraft, satellite and various ground-based observations, we carried out ground-space validation observations for macroscopic and micro cloud physical parameters retrieved by FY-4 satellite.The results have been used to serve for the Tianjin National Games.Meanwhile,we have demonstrated applying FY-4A products to the five-steps weather modification operation.(Operation Commanding and Running Centre)

2.3 Randomized rain enhancement experiment and impact evaluation

Randomized rain-enhancement experiments were continued in 2017 over the testing areas of four provinces.A total of 43 samples for rocket rain enhancement experiments and 2 samples for airplane rain enhancement experiments were conducted.During these experiments, all the relevant cloud and precipitation data from satellites, radars, upper-air soundings, surface raindrops, and ground rainfall, as well as rain enhancement data were collected timely to supplement and improve our sample database.A preliminary analysis of some examples of randomized rain enhancement experiment in 2017 has been carried out.

We have improved the impact evaluations of randomized rain enhancement experiments conducted over Shandong, Fujian, and Jilin provinces, and the corresponding software that are suitable for local ground rainfall, and also improved the evaluation method for their own radar-based and the corresponding software of rain enhancement experiment over Fujian and Hainan provinces.(Operation Commanding and Running Centre)

2.4 Rain enhancement potential and seeding technology in large cloud system over southern China

The project of “Rain Enhancement Potential and Seeding Technology in Large Cloud System over Southern China,” together with microwave radiometers, have established the statistical retrieval relationship between radar echoes and effective cloud droplet diameters in autumn and winter over Jiangxi Province,improved the cloud microphysical retrieval system with the FY-2 and the Sunflower stationary satellites,developed the satellite index of cold stratiform-cloud precipitation enhancement, conducted the development and improvement of the cloud microphysical retrieval system associated with the FY-4 high resolution stationary satellite, and carried out a cloud physical field detection experiment in Yibin of Sichuan Province.(Regional Centre Administration Office)

2.5 Optimizing a statistical effect analysis scheme for the non-randomized rain enhancement effectiveness evaluation

Studies were carried out in 2017 on the effects and scope of airplane rain enhancement experiment conducted in the winters of 2008 to 2014 on the seasonal rainfall over Jiangxi Province.Nine target stations and twelve downwind stations were selected as the studied objects according to the mean wind direction of 71 cloud-seeding operations in 7 years.A group of 5 control stations that provided the highest correlation of the mean seasonal precipitation with the selected 21 stations was determined.Linear regression equations between the control group and each downwind station were established.Key findings obtained from this study are summarized as follows.Average wintertime rainfall increased by 17.30% (p=0.25) and 21.67% (p=0.0013) for target and downwind regions, respectively.The results showed that the positive seeding effect can be detected as far as 126 km downwind of the target region.(Operation Commanding and Running Centre)

2.6 Results from the measurements of natural ice nuclear particles in Beijing during spring 2017

In these measurements, INPs concentrations were observed twice a day (09:00 am and 02:00 pm) in Beijing from Mar 20 to Apr 19, 2017 using the 5 Litters Bigg’s mixing cloud chamber.The methodology, time and sites of the observation are basically the same as those conducted in the years of 1963, 1995 and 1996.The observed activation temperatures were –10 °C, –15 °C, –20 °C, –25 °C, and –30 °C.Results show that INPs concentrations at the different activation temperatures have good consistency trend as diurnal variation.This is consistent with the observations obtained in 1963, 1995 and 1996.The INPs concentrations in the present observations are higher than those observed in 1963, but obviously lower than those observed in 1995 and 1996.This implies that natural changes and human activities in the past 20 years did not significantly increase the INPs concentration.During the observing period, because of weak precipitation occurring intermittently on Mar 20–25, the INPs concentrations decrease on these days.That is, precipitation has the effect of removing ice nuclei.The visibility sensor was also synchronized in this work.Results show that the trend of INPs concentrations and visibility is inversely correlated from day to day changes.The correlation coefficient between INPs concentrations at –25 °C and visibility is –0.51.Fog-haze weather occurred many times during the observing period, and in the absence of precipitation, visibility is directly affected by the severity of foghaze.The INPs concentrations have been compared to the other meteorological variables.Results show that the INPs concentrations have negative correlation with wind speeds but positive one with relative humidity,indicating that the better diffusion conditions, the less INPs.Inverse correlation between INPs and pressure was previously proposed, but found not obvious in the experiment.(Equipment R&D and Support Division)

2.7 Cloud and precipitation over the Tibetan Plateau

Using surface observations and FY-2E satellite TBB data from July 1 to August 31, 2014, we studied the characteristics of convective clouds and precipitation as well as raindrop size distribution over the Tibetan Plateau.Results show that convective activity appeared mainly in the central and southeastern part of the Tibetan Plateau and precipitation had a quasi-two-week cycle during the observational period.Because of solar heating, both convective clouds and precipitation had obvious diurnal variations.Few convective clouds occurred during the morning hours.Convective clouds first appeared at 11:00 BST, and then they merged,reaching to their maximum extent during 17:00–18:00 BST.At night precipitation tended to be advective and lasted until 6:00 BST when it began to dissipate.The mean cloud-top height was around 11.5 km ASL, and its maximum value exceeded 19 km ASL.The mean cloud-base height was 6.88 km ASL during the observing period.Precipitation was mainly short-lived, usually less than 1 h, in the form of shower with a mean intensity of 1.2 mm h–1.Results also show that the raindrop size distribution over the Tibetan Plateau was wider than that over the plain area at the same latitude and season, because rainfall could be more easily produced over the plateau than that over plain.Γ distribution was found to be more suitable for the raindrop size distribution than M-P distribution over the Tibetan Plateau.

In addition, multi-source satellite data from TRMM, CloudSat and Aqua and ground-based vertically pointing radar data are used to examine the vertical structure of a deep convective cell that occurred over Naqu during 13:00–16:00 BST on July 9, 2014 of the third Tibetan Plateau Atmospheric Science Experiment.Results show that (1) Radar reflectivity increased sharply across the 0 °C level, suggesting the important roles of melting solid precipitation particles in the deep convective cloud; (2) Bright bands appeared during its weakening period; (3) Deep convective clouds were composed mainly of ice particles, with considerable amount of small ice particles above 10 km and fewer large ones below 10 km; (4) Deep convective clouds contained mainly mixed-phase and glaciated processes (Fig.1) (Open Laboratory)

2.8 The relationship among PM2.5 concentration, visibility and PBL height during long-lived haze and fog-haze mixed events in Beijing

Using observations obtained by several state-of-art instruments, including Micro Pulse Lidar (model MPL-4B), particulate monitor (model TEOM 1405-DF), ceilometer (model CL31), visibility sensor (model PWD20) and profiling microwave radiometer (PMWR, model 3000A) as well as conventional meteorological instruments during the field campaign for haze and mixed fog-haze events in northern China, we investigated and quantified the relationship among PM2.5mass concentration, visibility and planetary boundary layer (PBL)height during four long-lived haze events and seven mixed fog-haze events from January 2014 to March 2015 in Beijing.Results show a negative exponential function between visibility and PM2.5mass concentration during both haze and mixed fog-haze events (with the sameR2of 0.80).However, the fog-haze events caused a more obvious decrease of visibility than that for haze events due to the formation of fog droplets that could induce higher light extinction.The PM2.5concentration had inversely linear correlation with the PBL height for haze events and negative exponential correlation for the mixed fog-haze events, indicating that the PM2.5concentration is more sensitive to the PBL height in the mixed fog-haze events.Visibility had positively linear correlation with the PBL height with theR2of 0.35 in the haze events and positive exponential correlation with theR2of 0.56 in the mixed fog-haze events.We also investigated the physical mechanism responsible for these relationships among visibility, PM2.5concentration and PBL height through the typical haze and mixed fog-haze event, and found that a double inversion layer formed in both typical events and played critical roles in maintaining and enhancing the long-lived polluted events.The variations of the double inversion layers were closely associated with the processes of long-wave radiative cooling during the nighttime and short-wave solar radiation reduction during the daytime.The upper-level inversion layer formed by the persistent southwest warm and humid airflow while the low-level inversion layer was initially produced by the surface long-wave radiative cooling during the night time and maintained by the reduction of surface solar radiation in the daytime.The obvious descending process of the upper-level inversion layer induced by the radiative process could be responsible for the enhancement of the low-level inversion layer and the lowering PBL height, as well as high aerosol loading for these polluted events.The reduction of surface solar radiation in the daytime could be about 35% for the haze events and 94% for the fog-haze mixed events.Therefore, the formation and subsequent descending of the upper-level inversion layer should be an important factor in maintaining and strengthening the long-lived severe pollution events, which has not been revealed by previous studies.The interactions between the PM2.5concentration and PBL height linked by radiative process caused a more significant and long-lasting deterioration of air quality and visibility in the mixed fog-haze events.The interactions of all these processes were particularly strong when the PM2.5mass concentration was larger than 150–200 μg m–3(Fig.2).(Open Laboratory)

2.9 Cloud chamber and seeding agents

We finished designing the structural and performance monitoring systems for a new warm-cloud chamber,and conducted some preliminary tests under an operational setting.Then, the main framework, the monitoring instrument selection, the mode and electric control and the display control cabinets of the chamber were designed and built.We set up a new IN-testing chamber, and transported and installed in Beijing.It is ready for various debugging.Some warm seeding agents experiments have been carried out in our Lab.Preliminary results show that the agents have some capability of influencing warm mist and fog.Some formula will be further improved(Fig.3).(Open Laboratory, Equipment R&D and Support Division)

3 Scientific achievements and applications

3.1 Operational running the Cloud Permitting Forecast System

The Cloud Permitting Forecast System (CPFS_V1.0) has been operationally running since July 28, 2017.The CPFS forecasts divide mainland China into 8 regions, with 31 forecast products released twice a day in real time at the temporal and spatial resolutions of 1 h and 3 km, respectively.As compared to the Weather Modification Forecast Model System (2013 Version), 5 additional forecast products, including cloud-base height and temperature, radar echo, cloud cover and relative humidity, are provided.With this model system,weather modification forecast service for different targets could be carried out.Based on the predicted cloud structures and evolution, potential seeding areas, timing and seeding plans can be executed with better service.(Operational Commanding and Running Centre)

3.2 Development of the seeding simulation technology and its operational effectiveness

We obtained simulations of flight and rocket seedings using CAMS cold-cloud seeding scheme.This allowed us to evaluate the effectiveness of multi-f l ight seeding to mixed-phase clouds, and rocket seeding to summer convective clouds.(Operation Commanding and Running Centre)

3.3 Supercooled water identification from airborne and remote sensing observations and their applications

A method to identify supercooled water from airborne particle spectrum and two-dimensional images was proposed based on DMT and PMS aircraft cloud physical detection.Through many case studies, we showed satellite-observed cloud characteristics in the super-cooled water and the ice cloud regions and developed a satellite-monitoring and identifying method for supercooled water regions by combining RGB composite images, T-Re relationship features and cloud parameter spectrum distribution.Through the space-time matching of aircraft detection and radar observations, the radar echo characteristics in the supercooled water area were statistically studied, and a method of synthetically identifying supercooled water areas using radar echo top temperature, echo intensity, and echo gradient was developed.Furthermore, an analysis software was designed to not only support the identification of weather modification conditions, but also assist in the aircraft icing monitoring and forecasting service.(Operation Commanding and Running Centre)

3.4 Impact evaluation of seeding different clouds

We have explored the development of reasonable impact evaluation methods for seeding different clouds with different operation modes in order to satisfy different business requirements, such as establishing a work flow and exploring new evaluation methods.The rationalities of these methods are consistent with operation modes and catalyst doses.That is, after selecting a contrast area, observation data from radar, satellite and surface rainfall are used to evaluate the impacts of cloud seeding.Two different methods are developed: (1)Regional Multi-Parameters Dynamic Evaluation for stratus clouds; (2) Echo Tracking Identification Evaluation for convective clouds.Both have been applied to the weather modification service in many important events.(Operation Commanding and Running Centre)

3.5 Development of the accurate processing analysis of cloud-precipitation system (APACS)

The accurate processing analysis of cloud-precipitation system (APACS) is a meteorological system that integrates cloud physics analysis technology, AuroView geographical information and image, and computing technology.The APACS has the function of accurate monitoring and predictive analysis of multi-scale cloudprecipitation physics variables.Aiming at the structural and evolution features of precipitation, this system can process observational data from multi-platforms (e.g., satellite, radar, sounding, rainfall, airborne microphysics measurements, and etc.).In addition, it can perform real-time comprehensive analyses of cloud structures and tracking recognition through integrated retrievals, and has the function of processing and analyzing multiscale dynamics and cloud physics products.On this basis, the APACS can have the operational functions of weather modification, such as the operating condition forecast analysis, monitoring and identification, seeding plan design, tracking control and seeding impact analysis, and can deal with different operational demands,such as precipitation enhancement by aircraft or rocket artillery and hail suppression.The APACS also has the functions of precipitation phase recognition, aircraft icing analysis and severe convection identification(rainstorm vs.hail) as well as producing many other special products.This system has been converted to scientific and operational versions (e.g., APACS 2.0, APACS -WMC, and APACS -NE series), respectively, in order to meet with different needs of scientific research and cloud seeding operation.We have obtained several software copyrights in 2017.Driven by the “Three-Year Weather Modification Project”, the APACS has been applied in more than 20 provinces and 400 cities.By supporting scientific research, weather modification operations and engineering projects, the core technology of this system has been continuously upgraded, which has plays an important role in conducting daily weather modification operations and in serving important events.(Operation Commanding and Running Centre)

3.6 A comprehensive weather modification system used in Northeast China

The National Weather Modification Center accepted a comprehensive weather modification system in Northeast China in 2017 after inspection.This system consists of “one platform and four systems”, which has enabled Northeast China to achieve technological progress in three areas as described below:

First, it has established an integrated operational platform (APACS-NE) that adapts to regional-provincial-city-county operational demands, fully supporting the five levels of weather modification operations.Second,all data at each level have been standardized and stored.Third, the information (instruction) transmission channels have built at all levels from the regions to provinces, cities, counties, and to the point of operation.Therefore, this system has the functions that “commands can go through, information can be collected from,and data can be stored” at all the levels.The core system architecture with “one platform and four systems”has been designed and realized with high interconnection in function and low coupling between systems,and can be flexibly disassembled and deployed.As an example of a typical weather modification operational system, the software and its structure are included in the Guide to the Construction of an Integrated Weather Modification Operation System and promoted to the whole country of China.(Operation Commanding and Running Centre)

4 Scientific field experiments

4.1 Aircraft observations during field experiments

From March to April 2017, seven airborne observation field experiments associated with Southwest vortices in Hubei were carried out in view of the to-be-tested fl ight plans in Yichang.From August to October 2017, a high-performance rain-enhancement aircraft was used for the first time in China to observe the peripheral clouds of a typhoon and test a joint real-time air-ground command system through a maritime satellite.This field experiment lasted for almost a month with six flights and collected aerosol and cloud microphysics data.We analyzed twelve aerosol vertical profiles obtained over Shenzhen, Guangdong Province and microphysical characteristics of shallow cumulus clouds in southern China.Results show that the aerosol number concentration near the ground varied greatly from 500 to 9000 cm–3under different weather conditions.Aerosol spectrum showed little variations in the daytime boundary layer, which were mainly bimodal or trimodal.On September 24’s flight ice particles in the forms of plate- and needle-shaped ice crystals were observed at 6 km altitude, where the minimum temperature was –6 °C as the aircraft was fl ying into the clouds(Fig.4).(Open Laboratory, Aircraft Operational Centre)

4.2 Cloud and fog observations over the Lushan Mountains

The Lushan cloud-fog field station resumed its operation after its re-construction in November 2015,and set up an observational platform equipped with modern instruments.Field experiments of cloud, fog and precipitation in Lushan were carried out in 2017, using the newly installed instruments, including fog-drop spectrometer, disdrometer, ceilometer, visibility sensor, micro-rain radar and automated meteorological station.A sizeable of observation data of cloud and fog and different precipitation cases have been obtained, such as freezing rain, snowfall, plume rain, rainstorm and etc.

The above observations taken during the autumn and winter of 2015 over the Lushan Mountains were analyzed.Results show that the cloud and fog droplet spectra have a bimodal pattern with double peak particle sizes at 6 μm and 12–15 μm, respectively, and the number concentration peaks of both particles reached the order of more than 10 μm–1cm–3with their maximum values as large as 93 μm–1cm–3.The cloud and fog droplet spectra were wide, with the particle size approaching drizzle drops.Precipitation was dominated by light rainfall.As the rainfall intensity increased, wider raindrop spectrum, and narrower cloud droplet spectrum could be seen, suggesting the presence of obvious in-cloud collision processes.Due to the high altitudes of the Lushan Mountains, the lower cloud base of precipitating clouds was the main reason for the presence of longlived cloud and fog.Abundant water vapor appeared after precipitation, prevailing in northerly winds with the average speed of 2.9–4.5 m s–1, which favors the formation of evaporation fog (Fig.5).(Open Laboratory,Equipment R&D and Support Division)

5 Weather modification operation and service

5.1 Weather modification commanding operation

We issue 7 types of satellite-retrieved cloud products, and 4 major categories with 20 sub-category model forecast products based on 3 modeling systems across China at a daily basis; collect real-time national fl ight and ground-based operational data; provide weekly weather modification requirements analysis, a weekly newsletter on “National Weather Modification in the Forthcoming Week”, a monthly newsletter on “National Weather Modification Qualify Report”, and a quarterly newsletter on “National Weather Modification Status”.

Relying on the continuous improvement of a fine cloud-precipitation forecast system and monitoringidentification techniques as well as operational design and command capability, we have provided cloud seeding service for North China, regional drought in Northeast China, the Bilahe and Wuma forest fire in Inner Mongolia, the 90th anniversary military parade, the Inner Mongolia 70th anniversary activity, the thirteenth National Sport Games in Tianjin and other service.In addition, we have published a total of 41 Cloud Seeding Potential Forecast Reports, 6 Early Warning Reports, and 5 Flight Plan Reports; organized 25 video conferences, released 2 quality reports on National Aircraft Operation Scheme Design, and 10 fl ight operations of weather modification all with satisfactory service to our customers.We have also accomplished several highimpact emergency disaster tasks, including the suppressing forest fire events in the Daxinganlin Mountains on 2 May 2017 and in Qinhuangdao on 25 April 2017.

The CPEFS_V1.0 operational model, with a 3 km horizontal resolution, has been used to predict the development of convective and stratiform clouds as well as their movement, vertical structures and precipitation.For example, its accurate 24 h forecasts played an important role in suppressing rainfall operations during a weather modification service to Inner Mongolia’s 70th anniversary activity, which was achieved by adding moveable rocket seeding equipment at its northwest defense areas.

During a suppressing forest-fire emergency service in Hulun Buir Bilahe, given the target forest-fire area and the performance of Xinzhou 60 aircraft, we designed a full seeding operation plan, in which a longduration seeding diffusion range was collocated with the Bilahe forest fire area, in order to achieve the best precipitation result at the target fire area.Results show that the 24 h cumulated rainfall in the fire area reached 39.2 mm after the seeding operation, while small to moderate rainfall occurred over the surrounding areas,indicating very obvious impact in rain enhancement.This work has been appreciated by the State Forestry Fire-Prevention Headquarter, and the Government of the Inner Mongolia Autonomous Region (Fig.6).(Operation Commanding and Running Centre, Aircraft Operational Centre)

5.2 Weather modification aircraft operation

(1) Drought resistance service in northeastern regions and other provinces.We have seriously provided services in drought-resistance, reservoir filling, environmental protection, and fire prevention over forest and grasslands using national weather modification aircrafts in the four northeastern provinces.To meet the needs of fire prevention over forest and grasslands during spring and summer, two weather modification aircrafts, i.e.,B-3435 and B-3726, based on Longjia airport in Changchun and Taoxian airport in Shenyang, respectively,were used to provide the services in drought resistance and reservoir filling over the Jiagedaqi region in Heilongjiang and Hulun Buir in Inner Mongolia.

To meet the requirements of drought-resistance and normal seeding over the Central Plains and Hetian,the weather modification aircraft B-3726, based on Xinzheng Airport in Henan and Hetian Airport in Xinjiang,provided aircraft seeding service over their regions and neighboring areas, in collaboration with the Weather Modification Departments of Henan Province and Xinjiang Autonomous Region.(Aircraft Operational Centre)

(2) Research to operation transformation and foreign exchange.A Weather Modification Airborne Observing Laboratory was set up in China Meteorological Science Park in Changping, jointly with the Huayun Meteorological Technology Group Corporation in order to provide an open platform for weather modification aircraft-observing equipment, conduct scientific research and application, improve equipment performance with technological innovation, and facilitate research-to-operation transformation, and technical consulting.Therefore, the laboratory is expected to provide a solid weather modification aircraft platform and strong support for reliable operation of on-board cloud physics detection equipment.

To conduct the operational mini-project of the CMA’s “The Full-Range Monitoring and Control of Operational Weather-Modification Seeding Ammunition Demonstration” and the CAMS’ special science project of “Application of Tracers to Evaluating Rain-Enhancement Effects” as well as the other scientific studies, we took charge of establishing “the Standardization of Coding Technological Criteria for Weather Modification Equipment and Seeding Ammunitions” and “How to Monitor and Manage Weather Modification Equipment and Seeding Ammunitions”.In addition to formulating the technology criteria, we promoted their applications nationwide.

We have actively participated in foreign exchange and collaborative activities by sending some staff to the United States to receive training on the use and maintenance of airborne remote sensing equipment such as airborne cloud particle detection equipment and laser radar; and actively attending seminars and lectures held by experts from domestic universities and research institutions on aerosol and cloud and precipitation physics.Moreover, the training and technical exchange of on-board detection equipment applications were carried out in collaboration with the USA’s DMT (Droplet Measurement Technologies) company, which strengthened the cultivation of young scientific and technologic talents and the construction of a professional team of national aircraft operation and management.(Aircraft Operational Centre)

(3) Detective equipment and aircraft maintenance.The regular inspection and calibration of the DMT particle measurement system were completed in accordance with the required procedures.The fixed inspection and maintenance of two Xinzhou 60 aircraft are organized and implemented, i.e., 12 months (Yichang), 18 months (Luoyang), and 24 months (Yanliang); and the trusteeship of Kingair and Xinzhou 60 aircraft was bided.(Aircraft Operational Centre)