上海創(chuàng)智天地廣場(chǎng)熱舒適分析與評(píng)價(jià)

魏冬雪 劉濱誼

1個(gè)世紀(jì)以來，地域氣候?qū)υO(shè)計(jì)的影響從人們居住的室內(nèi)空間走向人們活動(dòng)的戶外空間，成為多學(xué)科關(guān)注的焦點(diǎn)。在全球氣候變化和快速城市化的影響下，中國(guó)風(fēng)景園林學(xué)者正在積極關(guān)注氣候?qū)Τ鞘袘敉饪臻g環(huán)境的影響。本課題組已經(jīng)針對(duì)上海“三類九種”城市戶外空間開展了持續(xù)3年的研究。

在城市廣場(chǎng)類別中，圍繞風(fēng)景園林小氣候系統(tǒng)功效形成要素、風(fēng)景園林小氣候適應(yīng)性空間要素與空間形態(tài)結(jié)構(gòu)和風(fēng)景園林小氣候適宜性物理評(píng)價(jià)與感受評(píng)價(jià)已取得一些成果[1-4]。依托于景觀環(huán)境形象、環(huán)境生態(tài)綠化、大眾行為心理三元素對(duì)于人們環(huán)境感受所起的作用是相輔相成、密不可分的這一理論支撐[5]，本研究嘗試探索城市廣場(chǎng)空間形態(tài)、熱環(huán)境和使用者心理感知之間的關(guān)系。

1 研究方法

1.1 實(shí)驗(yàn)場(chǎng)地

上海市地處東經(jīng)120°52′～122°12′，北緯30°52′～31°53′，平均海拔4m；屬亞熱帶季風(fēng)性氣候，為夏熱冬冷氣候區(qū)，7、8月份氣溫最高。

本研究的實(shí)驗(yàn)地——上海創(chuàng)智天地廣場(chǎng)位于楊浦區(qū)創(chuàng)智天地產(chǎn)業(yè)園區(qū)內(nèi)，廣場(chǎng)整體下沉4m，四周有25m高的商業(yè)寫字樓。如圖1所示，廣場(chǎng)總平面成T字形，主廣場(chǎng)為東北—西南走向(北偏東60°)，長(zhǎng)約120m，寬約50m，副廣場(chǎng)與主廣場(chǎng)垂直，長(zhǎng)約120m，寬約40m。圖1中標(biāo)注了廣場(chǎng)區(qū)、懸挑區(qū)和草坪區(qū)3個(gè)部分及測(cè)試點(diǎn)位置。圖2是各區(qū)人視及魚眼照片；場(chǎng)地空間形態(tài)測(cè)量?jī)x器主要有魚眼鏡頭和超聲波測(cè)距儀。各區(qū)空間形態(tài)基本情況見表1。

表1 各測(cè)點(diǎn)空間形態(tài)基本情況Table 1 Spatial morphology of each area

1.2 小氣候測(cè)試

本研究測(cè)試了空氣溫度、相對(duì)濕度、風(fēng)速和太陽輻射等小氣候因子。測(cè)試儀器采用美國(guó)生產(chǎn)的Watchdog小型氣象站。設(shè)備裝配在1個(gè)1.5m高的三腳架上，與成人頭部、頸部高度接近，設(shè)定為每10min自記1次。

實(shí)驗(yàn)在2016年的8月、11月和12月晴朗少云的天氣進(jìn)行，夏秋兩季各3天，冬季4天，共計(jì)10個(gè)測(cè)試日。每個(gè)測(cè)試日的實(shí)驗(yàn)開始時(shí)間為7：00；結(jié)束時(shí)間受到日落的影響：夏季為18：30，秋季為17：30，冬季為17：00。

1.3 熱舒適指標(biāo)

本研究選擇生理等效溫度(PET)作為熱舒適評(píng)價(jià)指標(biāo)。它被定義為在某一室內(nèi)或戶外環(huán)境中，人體皮膚溫度和體內(nèi)溫度達(dá)到與典型室內(nèi)環(huán)境同等的熱狀態(tài)時(shí)所對(duì)應(yīng)的氣溫。盡管預(yù)測(cè)平均投票(PMV)、標(biāo)準(zhǔn)有效溫度(SET＊)和生理等效溫度(PET)3個(gè)指標(biāo)均基于人體能量平衡，但生理等效溫度(PET)更適用戶外熱舒適評(píng)估[6]。

1.4 問卷調(diào)查

受訪者為自發(fā)在廣場(chǎng)上進(jìn)行休閑活動(dòng)的人們，調(diào)研問卷包含受訪者的基本信息、實(shí)時(shí)熱感覺和熱認(rèn)知3個(gè)部分?；拘畔⒂涗浭茉L者的性別、年齡、身高、體重、衣著、活動(dòng)狀態(tài)、在外活動(dòng)時(shí)間等；實(shí)時(shí)熱感覺記錄受訪者總的熱感覺、熱舒適、熱可接受度和熱偏好，以及對(duì)各小氣候因子的感知和偏好；熱認(rèn)知記錄受訪者對(duì)四季、廣場(chǎng)各空間的舒適判定及來訪原因和目的等內(nèi)容。

熱感覺投票(TSV)使用9點(diǎn)標(biāo)度(非常冷、冷、微冷、涼、不冷不熱、暖、微熱、熱、非常熱)，熱舒適投票(TCV)使用4點(diǎn)標(biāo)度(非常不舒適、不舒適、舒適、非常舒適)，熱偏好投票(TPV)使用3點(diǎn)標(biāo)度(變冷、不變、變熱)，各小氣候因子的熱感覺和熱偏好分別使用5點(diǎn)和3點(diǎn)標(biāo)度。

圖1 創(chuàng)智天地廣場(chǎng)測(cè)點(diǎn)圖Fig. 1 Distribution map of mini meteorological stations on the square

圖2 3個(gè)測(cè)點(diǎn)人視、魚眼照片F(xiàn)ig. 2 Human view and fish eye photos in the three areas

2 結(jié)果

2.1 各測(cè)點(diǎn)小氣候情況

10個(gè)測(cè)試日中各測(cè)點(diǎn)小氣候因子總體情況如下：空氣溫度范圍1.7～36.8℃，相對(duì)濕度范圍30.4%～97.1%，風(fēng)速范圍0～4.5m/s，太陽輻射范圍30～1073wat/m2。圖3～6是夏秋冬各季節(jié)各測(cè)點(diǎn)空氣溫度、相對(duì)濕度、風(fēng)速和太陽輻射4種小氣候因子逐時(shí)平均值變化圖。總體上，各測(cè)點(diǎn)空氣溫度和相對(duì)濕度變化較為一致，差別較?。惶栞椛浜惋L(fēng)速差別較大。夏秋冬三季太陽輻射總趨勢(shì)為廣場(chǎng)區(qū)＞草坪區(qū)＞懸挑區(qū)，此趨勢(shì)與SVF關(guān)系一致。冬季草坪區(qū)太陽輻射略高于廣場(chǎng)區(qū)，原因在于草坪區(qū)更早獲得日照；風(fēng)速總趨勢(shì)為懸挑區(qū)＞廣場(chǎng)區(qū)＞草坪區(qū)，懸挑區(qū)由于產(chǎn)生了狹管效應(yīng)，風(fēng)速最大。

2.2 問卷情況

夏秋冬三季共獲得870份有效問卷。秋季問卷356份，夏季問卷280份，冬季問卷234份問卷(表2)。

2.2.1 熱感覺、熱舒適與熱期望

圖7是夏秋冬三季熱感覺分布情況。一半以上的人在秋冬兩季均能獲得中性熱感覺，在夏季感覺微熱至非常熱(TSV=2，3，4)占比41.4%，在冬季感覺到微冷和冷占比22.4%。夏秋冬三季感知舒適和非常舒適的占比依次為84.7%、91.6%、76.5%，秋季最高，冬季最低。夏季，62.9%的人期望更加涼爽，冬季，59.8%的人期望更加溫暖。

圖3 夏秋冬測(cè)試日空氣溫度均值Fig. 3 Hourly mean change of air temperature in summer, autumn and winter

圖4 夏秋冬測(cè)試日相對(duì)濕度均值Fig. 4 Hourly mean change of relative humidity in summer, autumn and winter

圖5 夏秋冬測(cè)試日太陽輻射均值Fig. 5 Hourly mean change of solar radiation in summer, autumn and winter

圖6 夏秋冬測(cè)試日風(fēng)速均值Fig. 6 Hourly mean change of wind speed in summer, autumn and winter

圖7 夏秋冬三季熱感覺投票占比Fig. 7 Thermal sensation votes in summer, autumn and winter

表2 870份問卷對(duì)應(yīng)的小氣候概況Table 2 Micro-climate conditions of the 870 questionnaires

為了揭示人們?cè)谙亩瑑杉緹岣杏X和熱舒適的不對(duì)應(yīng)性，本研究進(jìn)一步分析熱感覺和熱舒適值之間的關(guān)系。圖8顯示了夏秋冬三季每一級(jí)熱感覺所對(duì)應(yīng)的熱舒適投票平均值，其二項(xiàng)式如下：

熱感覺與熱舒適的關(guān)系隨著季節(jié)發(fā)生變化：夏季，當(dāng)TSV為0.32時(shí)，人們感覺最為舒適；秋季，當(dāng)TSV為0.42時(shí)，人們感覺最為舒適；冬季，當(dāng)TSV為2.04時(shí)，人們感覺最為舒適。

同樣的方法被用來揭示熱偏好投票與熱感覺之間的關(guān)系(圖9)，所得一元回歸方程如下：

夏秋冬三季人們偏好不變時(shí)所對(duì)應(yīng)的熱感覺分別為-1.72、0.87和1.44，人們?cè)谙募酒谕記鏊?，在秋冬兩季期望更加溫暖?/p>

使用斯皮爾曼等級(jí)相關(guān)分析法進(jìn)一步揭示熱感覺、熱舒適和熱期望與小氣候要素及PET之間的關(guān)系?？諝鉁囟取ET與熱感覺和熱舒適顯著正相關(guān)，與熱期望顯著負(fù)相關(guān)，熱舒適與空氣溫度和PET的相關(guān)系數(shù)較低(表3)。

2.2.2 熱中性溫度與熱舒適范圍

由于熱感覺與熱舒適隨著季節(jié)變化而變化，按季節(jié)計(jì)算熱中性溫度和舒適范圍變得十分必要。使用PET作為客觀評(píng)價(jià)指標(biāo)，首先計(jì)算每一度PET對(duì)應(yīng)的熱感覺均值，從而計(jì)算熱中性溫度和熱中性范圍(圖10)。

當(dāng)T S V=0時(shí)，夏秋冬各季對(duì)應(yīng)的PET分別為19.6℃、22.5℃和23.6℃。TSV在-0.5～0.5對(duì)應(yīng)的中性范圍分別為19.6±5.9℃PET、22.5±10.4℃PET、23.6±7.1℃PET。

使用同樣方法計(jì)算每一度PET對(duì)應(yīng)的熱舒適范圍(圖11)，夏秋冬各季最為舒適時(shí)對(duì)應(yīng)的PET值分別為17.5℃、22.9℃和30℃；當(dāng)TCV≥1時(shí)對(duì)應(yīng)的舒適范圍分別為17.5±4.1℃PET、22.9±9.2℃PET和30±6.8℃PET。

為了便于與國(guó)歌廣場(chǎng)所獲得的數(shù)據(jù)進(jìn)行比較，本研究計(jì)算了夏秋冬三季平均熱感覺、平均熱舒適與生理等效溫度之間的關(guān)系(圖12)。

當(dāng)TSV=0時(shí)，熱中性值為20.8℃PET，當(dāng)TSV在-0.5～0.5時(shí)，熱中性范圍為20.8±6.4℃PET；當(dāng)PET為23.8℃時(shí)，人們最為舒適，當(dāng)TCV≥1時(shí)，對(duì)應(yīng)的熱舒適范圍為23.8±6.6℃PET。

圖8 熱感覺投票與平均熱舒適之間的關(guān)系Fig. 8 Relationship between TSV and TCV

圖9 熱感覺投票與平均熱偏好之間的關(guān)系Fig. 9 Relationship between TSV and TPV

圖10 生理等效溫度與平均熱感覺投票之間的關(guān)系Fig. 10 Relationship between MTSV and PET

圖11 生理等效溫度與平均熱舒適投票的關(guān)系Fig. 11 Relationship between MTCV and PET

圖12 三季平均熱感覺、熱舒適與生理等效溫度之間的關(guān)系Fig. 12 Relationship among MTSV, MTCV and PET in three seasons

2.2.3 小氣候要素?cái)?shù)感知與偏好

夏季60%以上的訪問發(fā)生在懸挑區(qū)，秋冬兩季，90%以上的訪問發(fā)生在廣場(chǎng)區(qū)。圖13是夏秋冬三季小氣候要素感知占比。在夏季，感知溫度適中的人占比為65%，34.7%的人認(rèn)為空氣溫度高，感知濕度和風(fēng)速適中的人占比分別為77.1%和60.4%，感知日照適中的占比為36.1%，有47.2%的人認(rèn)為日照低；在秋季，感知溫度和濕度為適中的人占比最大，分別為69.1%和68.5%，67.8%的人感知風(fēng)速低，42.7%的人感知日照低；冬季，溫度與日照感知較為一致，感知適中的占比分別為53%和54.3%，感知低的占比分別為46.6%和40.2%；風(fēng)速和濕度的感知以適中居多，分別為95.3%和71.8%。

圖14是3個(gè)季節(jié)人們對(duì)小氣候要素偏愛占比情況。夏季，人們期望溫度、濕度和日照均降低，占比分別為69.3%、25.7%和37.9%，41.1%的人期望風(fēng)速升高；秋季，對(duì)溫度、濕度、風(fēng)速和日照期望不變的占比均超過60%，期望溫度、日照升高的占比均為36%；冬季，期望溫度和日照升高的人分布為57.3%和59.4%，期望風(fēng)速降低的人為40.2%，84.2%的人期望濕度不變。3個(gè)季節(jié)中，大多數(shù)人都期望濕度不變；人們?cè)谙募酒谕偷臏囟取⑷照蘸透叩娘L(fēng)速，冬季則剛好相反。

使用斯皮爾曼等級(jí)相關(guān)分析法進(jìn)一步揭示小氣候偏好與小氣候要素值之間的關(guān)系如下：溫度偏好、風(fēng)速偏好和日照偏好受空氣溫度影響顯著。

2.2.4 熱認(rèn)知情況

表3 熱感覺、熱舒適和熱期望與小氣候要素及PET的相關(guān)性Table 3 Correlation analysis between micro-climatic factors and preference votes

對(duì)四季不舒適的投票占比中，夏季超過90%，冬季50%，夏秋各10%；在夏季超過70%的認(rèn)為廣場(chǎng)區(qū)不舒適，秋冬兩季超過80%的人認(rèn)為懸挑區(qū)不舒適，前者是因?yàn)楸瘢笳呤怯捎跓o陽光和風(fēng)大；3個(gè)季節(jié)中人們對(duì)草坪區(qū)的舒適認(rèn)知均比較低，僅10%。如圖15所示，開闊、熱舒適、離家近是人們來此廣場(chǎng)的主要原因，在夏季，熱舒適占比最高；在秋冬兩季，開闊占比最高。

2.3 場(chǎng)地舒適空間評(píng)估

將3個(gè)空間在夏、秋、冬各季的生理等角溫度均值與各季節(jié)熱舒適范圍相比較，如圖16所示，在夏季，3個(gè)空間的生理等效溫度均高于舒適上限，懸挑區(qū)最靠近舒適范圍；秋季，懸挑區(qū)在舒適范圍之外，廣場(chǎng)區(qū)、草坪區(qū)對(duì)應(yīng)舒適時(shí)間占比分別為65.7%、76.6%；冬季，只有草坪區(qū)在正午能夠達(dá)到舒適范圍。

圖13 夏秋冬三季小氣候要素感知占比Fig. 13 Percentage of micro-climatic perception in summer, autumn and winter

圖14 夏秋冬三季小氣候要素偏愛占比Fig. 14 Percentage of micro-climatic preference in summer, autumn and winter

圖15 夏秋冬三季來廣場(chǎng)原因投票百分比Fig. 15 Votes of reasons for coming to the square in summer, autumn and winter

圖16 夏秋冬各空間生理等效溫度隨時(shí)間變化圖Fig. 16 The changes of pet of each space in summer, autumn and winter with time

3 討論

3.1 廣場(chǎng)形態(tài)與熱環(huán)境

朝向、高寬比(H/W)、天空視覺因子(SVF)等形態(tài)因子對(duì)城市熱環(huán)境影響顯著[7]。在本研究中，3個(gè)測(cè)點(diǎn)的空氣溫度和相對(duì)濕度在各季節(jié)變化較為一致且差異不明顯，這與課題組使用計(jì)算機(jī)模擬結(jié)果較為一致，模擬發(fā)現(xiàn)廣場(chǎng)高寬比及朝向?qū)諝鉁囟群拖鄬?duì)濕度無明顯影響，對(duì)風(fēng)影響顯著[8]。廣場(chǎng)各測(cè)點(diǎn)風(fēng)環(huán)境比較復(fù)雜，懸挑區(qū)有較大的風(fēng)速主要原因可能是“狹管”效應(yīng)，懸挑上方建筑物的遮擋，使得下方局部風(fēng)速增大；廣場(chǎng)區(qū)的風(fēng)速大于草坪區(qū)可能是由于廣場(chǎng)區(qū)更低的高寬比產(chǎn)生了“風(fēng)掃”效應(yīng)；懸挑區(qū)的太陽輻射受SVF影響顯著，廣場(chǎng)區(qū)與草坪區(qū)的太陽輻射差異較小的原因可能在于SVF與太陽輻射的關(guān)聯(lián)度，有學(xué)者通過計(jì)算機(jī)模擬發(fā)現(xiàn)，當(dāng)SVF值從0.1逐漸增大到0.5時(shí)，SVF與熱環(huán)境的關(guān)聯(lián)度值逐漸降低[9]。

3.2 熱中性與熱舒適

熱中性是人們感覺不冷不熱的狀態(tài)，熱舒適是人們對(duì)熱環(huán)境表示滿意的意識(shí)狀態(tài)。本研究發(fā)現(xiàn)各季節(jié)之間人們的熱中性差值為1～3℃PET，這一差值略高于Cohen和Lin的研究[6，10]。人們?cè)诟鳠崾孢m的差值高達(dá)5～10℃PET，顯著表明在夏季越?jīng)鏊绞孢m，冬季越溫暖越舒適。各季節(jié)的熱中性和熱舒適的范圍相比較，秋季最寬，冬季其次，夏季最窄，這與人們對(duì)廣場(chǎng)熱認(rèn)知結(jié)果一致，人們認(rèn)為在廣場(chǎng)夏季熱環(huán)境較為嚴(yán)峻。

3.3 廣場(chǎng)形態(tài)與熱認(rèn)知

廣場(chǎng)區(qū)與草坪區(qū)擁有相似的熱環(huán)境，人們對(duì)廣場(chǎng)區(qū)的熱認(rèn)知卻遠(yuǎn)遠(yuǎn)高于草坪區(qū)，這可能受到廣場(chǎng)形態(tài)與人們活動(dòng)需求的綜合影響。在夏季，熱舒適作為人們來廣場(chǎng)區(qū)活動(dòng)的主要原因時(shí)，人們判斷懸挑區(qū)最舒適；在秋冬兩季，空間開闊成為人們來廣場(chǎng)活動(dòng)的最主要原因時(shí)，人們判斷廣場(chǎng)最舒適。本研究進(jìn)一步支持了Lenzholzer提出的人們視覺認(rèn)知或空間認(rèn)知與小氣候認(rèn)知存在關(guān)聯(lián)性[11]。

3.4 兩個(gè)廣場(chǎng)熱中性范圍比較

本研究比較了創(chuàng)智天地廣場(chǎng)與國(guó)歌廣場(chǎng)熱中性范圍的差異，創(chuàng)智天地廣場(chǎng)熱中性范圍為14～27℃PET，國(guó)歌廣場(chǎng)熱中性范圍7～25℃PET，后者較前者更為寬廣。2個(gè)廣場(chǎng)受訪者經(jīng)歷的空氣溫度范圍基本一致，因此并不能像比較不同地區(qū)的中性范圍一樣將其歸因于空氣溫度變化范圍寬窄；從受訪人群上也很難將其歸因于社會(huì)文化差別。Nasir曾證實(shí)在特定的小氣候環(huán)境中人們的活動(dòng)偏好和熱感知顯著相關(guān)[12]，廣場(chǎng)形態(tài)和人們活動(dòng)的耦合作用可能影響了人們的熱中性范圍。作為活動(dòng)的發(fā)生器，創(chuàng)智天地廣場(chǎng)上的受訪者活動(dòng)類型單一，僅僅駐足、坐憩，而國(guó)歌廣場(chǎng)有更多的綠色覆蓋和更小的空間單元，促進(jìn)了打拳、散步、跳舞等活動(dòng)的發(fā)生。

4 結(jié)論

本文對(duì)上海創(chuàng)智天地廣場(chǎng)進(jìn)行了夏秋冬三季共計(jì)10d的小氣候物理實(shí)驗(yàn)和大眾心理感知研究，驗(yàn)證了廣場(chǎng)空間形態(tài)、熱環(huán)境與人的心理感知三者之間密切相關(guān)。

廣場(chǎng)朝向、高寬比(H/W)、天空視覺因子(SVF)等形態(tài)因子與熱環(huán)境關(guān)系緊密：更小的SVF適用于夏季，更大的SVF適合于秋冬兩季；熱舒適是比熱中性更為狹窄的范圍并且更難獲得，熱舒適與熱感覺均與空氣溫度和PET顯著相關(guān)，熱感覺與空氣溫度和PET的相關(guān)系數(shù)更高。人們的熱感覺與熱認(rèn)知較為一致的是廣場(chǎng)夏季熱環(huán)境較為嚴(yán)峻，空間開闊是人們?cè)谇锒瑑杉緛韽V場(chǎng)的主要原因，它影響了人們對(duì)廣場(chǎng)各區(qū)的熱認(rèn)知；創(chuàng)智廣場(chǎng)的熱中性范圍低于國(guó)歌廣場(chǎng)，國(guó)歌廣場(chǎng)空間形態(tài)與人們活動(dòng)的耦合可能影響了人們的熱中性范圍。

遮陰與開闊是上海地區(qū)廣場(chǎng)設(shè)計(jì)的必備條件。未來的研究將繼續(xù)關(guān)注空間開闊對(duì)熱認(rèn)知的影響以及空間形態(tài)與行為活動(dòng)的耦合對(duì)熱中性范圍的作用，進(jìn)一步揭示廣場(chǎng)空間形態(tài)、熱環(huán)境與心理感知之間的關(guān)系，為創(chuàng)造更加適宜的廣場(chǎng)空間提供依據(jù)。

表4 小氣候偏好與小氣候要素的相關(guān)性Table 4 Correlation analysis among TSV, TCV, TPV and micro-climate factors

注：文中圖片均由作者繪制。

致謝：感謝同濟(jì)大學(xué)建筑與城市規(guī)劃學(xué)院提供的幫助；感謝博士生連澤峰、劉鳴以及碩士生李凌舒對(duì)數(shù)據(jù)收集提供的幫助。

The Analysis and Evaluation of Thermal Comfort at Shanghai Knowledge & Innovation Community Square

Wei Dongxue, Liu Binyi

Under the influence of global climate change and rapid urbanization, Chinese landscape architects are paying positive attention to the impact of climate on urban outdoor environment.Research on Micro-climate Responsive Design Theory and Method of Landscape Architecture in Urban Livable Environment(2014—2018) was the first and only key project supported by the National Natural Science Foundation of China (NSFC) in the Chinese landscape architecture field. The research group has carried out a continuous 3-year study on the "three categories and nine types" of outdoor environment in Shanghai. The research group focused on the coupling of 3 core landscape micro-climatic issues:(1) system function including wind, wetness and hotness; (2) spatial elements and spatial forms, and(3) the perception of landscape micro-climate which includes theory, methodology, technology, and case study and verification, with some achievements made in the study of urban squares. Relying on the theory that the spatial form, greening ecology,the human psychology and behavior influences people's perception of the environment, this study attempted to explore the relationship among urban square space form, thermal environment and users'psychological perception.

The investigation was conducted at the KIC Square in Shanghai. Shanghai is located at 120°52'E～122°12'E, 30°52'N～30°52'N, at an altitude of 4m, characterized by a subtropical monsoon climate, hot in summer and cold in winter,with the highest temperature in July and August every year. The KIC Square is located in Yangpu District Industrial Park. The square sinks 4 meters,and is surrounded by office buildings of the height of 25m. The plane of the square is in T shape. The square area (H/D=0.3, SVF=0.612, N-E 60°), the overhang area (H/D=0.6, SVF=0.142, N-E 60°)and the lawn area (H/D=0.6, SVF=0.504, N-W 30°) were chosen as the test spots. Watchdog mini meteorological station manufactured in U.S.was adopted as the test instrument with the data recorded every 10 minutes. All instruments were placed at a height of 1.5m above the ground on tripods. The experiments were all carried out on sunny and cloudless days in August, November,and December of 2016, with 3 days in summer and autumn respectively, 4 days in winter, and 10 test days in total. In this study, physiological equivalent temperature (PET) was selected as the index of thermal comfort evaluation. The interviewees of the questionnaire were people who had spontaneous leisure activities on the square. The questionnaire consisted of three parts: basic information,instantaneous thermal sensation and thermal cognition.

In the 10 days of the experiment, the air temperature varied from 1.7℃to 36.8℃, the relative humidity varied from 30.4% to 97.1%, the wind speed varied from 0～4.5m/s, and the solar radiation varied from 30wat/m2to 1073wat/m2.Overall, the changes of air temperature and relative humidity in each measuring point were consistent;the difference of solar radiation and wind speed in each measuring point was bigger. The general trend of solar radiation was square area ＞ lawn area ＞overhang area in the three seasons, and the trend was consistent with SVF. The solar radiation in lawn area was slightly higher than that in square in winter since the lawn area got sunshine earlier. The general trend of wind speed was overhang area ＞ square area ＞ lawn area, and the maximum of wind speed was produced by the narrow pipe effect in overhang area.

870 valid questionnaires were obtained for the three seasons separately, with 280 for summer,356 in autumn and 234 in winter. More than half of the people would have neutral thermal sensation in autumn and winter. In summer, 41.4% people felt slight hot (TSV=2) to very hot (TSV=4); and in winter,22.4% people felt slight cold and very cold. The proportion of perception of being comfort and very comfort in summer, autumn and winter was 84.7%,91.6% and 76.5% respectively, with the highest in autumn and the lowest in winter. 62.9% people expected it to be cooler in summer and 59.8%people expected it to be warmer in winter.

The relationship between thermal sensation and thermal comfort varied with season changes: the most comfortable condition was at a TSV of 0.32 in summer, 0.42 in autumn, and 2.04 in winter. People prefer "no change" at a TSV of -1.72 in summer, 0.87 in autumn, and 1.44 in winter. It expected to be cooler in summer and warmer in autumn and winter.Ta and PET were positively correlated with thermal sensation and thermal comfort, while negatively correlated with thermal preference. Correlation coefficients among thermal comfort and Ta, PET were relatively low.

The average thermal sensation of each PET was calculated to obtain the thermal neutral temperature and thermal neutral range. In summer, autumn and winter, the corresponding PET at TSV=0 was 19.6℃, 22.5℃ and 23.6℃respectively. When TSV was -0.5～0.5, the corresponding thermal neutral ranges were 19.6±5.9℃PET, 22.5±10.4℃PET, 23.6±7.1℃PET.The most comfortable condition was at a PET of 17.5℃ in summer, 22.9℃ in autumn, and 30℃ in winter. When TCV ≥1, the corresponding thermal comfortable ranges were 17.5±4.1℃PET,22.9±9.2℃PET and 30±6.8℃PET. The relationship among the average thermal sensation, average thermal comfort and PET in the three seasons were calculated. With TSV=0, the PET value was 23.8℃, and when TSV was during -0.5 to 0.5,people's thermal neutral range was 20.8±6.4℃PET.The most comfortable condition was at a PET of 23.8℃ with TCV ≥1, and the corresponding thermal comfortable range was 23.8±6.6℃PET.

In summer, more than 60% visits occurred in the overhang area while more than 90% visits took place in the square area in other seasons. In general, most people expected unchanged humidity,lower air temperature, higher solar radiation and higher wind speed in summer, as opposite in winter.As indicated by the experiment data, air temperature largely affects people's preference for air temperature, wind speed and solar radiation.

90% of the interviewees thought that summer was unpleasant, 50% thought it was unpleasant in winter, and 10% considered spring and autumn as uncomfortable. In summer, more than 70% thought it was uncomfortable on the square, and more than 80% felt uncomfortable in the overhang area in winter. The former was due to the exposure to sunshine, and the latter was due to insufficient sunshine and strong wind. In summer, autumn and winter,the comfortable cognition of lawn area was low, with the percentage of only 10%. Open, thermal comfort and close to home were the main reasons for people to come to this square. In summer, the proportion of thermal comfort was the highest while the proportion of openness was the highest in autumn and winter.

The PET of the the three area was higher than the upper limit of comfort in summer, and the overhang area was most close to the upper limit of the comfort range. In autumn, the overhang area was outside the range of comfort, and the proportion of the comfort time corresponding to the square area and the lawn area was 65.7% and 76.6%. In winter,only the lawn area could reach the comfort zone at noon.

This study compared thermal neutral range between the KIC Square and the Guoge Square, with the former as 14～27℃PET, and the latter as 7～25℃PET, which shows that the Guoge Square has a broader range of thermal neutrality than that of the KIC Square. This study speculated that the coupling of square forms and people's activities may cause the thermal neutral differences between the two squares. As the generator of activities, the types of activities at the KIC Square were comparatively less, with the forms of just sitting and walking. More green coverage and smaller square segmentation at the Guoge Square promotes more kinds of activities such as boxing, walking, and dancing.

Through the 10-day of microclimatic physical experiment and public psychological perception in three seasons (summer, autumn and winter) at the KIC Square, the study of this paper has proved a close relationship among space form, thermal environment and human psychological perception.

The orientation, aspect ratio (H/W) and sky vision factor(SVF) closely relate to the thermal environment: smaller SVF is suitable for summer, and larger SVF is suitable for autumn and winter. The thermal comfort range is narrower and harder to be obtained than the thermal sensation range.Both thermal comfort and thermal sensation significantly relate to air temperature and PET, and the correlation coefficient of thermal comfort is much lower than thermal sensation. The thermal perception and thermal cognition of human being are more consistent in summer when the thermal environment is more severe in the square. Openness is the main reason for people to come to the square in autumn and winter, which largely affects people's cognition.Thermal neutral range of the KIC Square is lower than that of the Guoge Square, which might be due to the coupling of space form and people's activities.

Shading and openness should be inevitable elements for the design of the squares in shanghai. It is suggested that future research could pay more attention to the influence of openness on thermal cognition and the coupling effect of space form and people's activities, to further reveal the relationship among the square space form, the thermal environment and the psychological perception, and finally provide the basis for the creation of a more suitable square space.

(Editor / Jin Hua)