塔中紫外辐射与气象要素的关系

Relationships between UV Radiation and Meteorological Factors in the Tazhong Region of the Taklimakan Desert

分析2007年塔克拉玛干沙漠腹地紫外辐射特征和影响因子与气象要素的相关性,并依据有关要素拟合出紫外辐射的估算方程。结果表明:紫外辐射年总量达到305.64 MJ/(m2.a),7月最大,12月最小,全年瞬时强度峰值在6月,为67.11 W/m2。紫外辐射的变化与总辐射变化呈显著正相关,且紫外辐射在总辐射中所占比例夏季大,冬季小,春、秋季居中。紫外辐射受云量和沙尘影响很大。与晴天相比,阴天紫外辐射减少31.68%,沙尘暴天气减少41.91%。单纯从年变化和日变化来看,紫外辐射与气温、地表温度呈正相关,其变化趋势基本一致,夏季最大,春、秋季次之,冬季最小,或早晚小中午大。与气温相比,地表温度与紫外辐射的相关性在夏季最好。水汽没有直接吸收紫外辐射,紫外辐射与比湿除了在冬季有较弱的相关性外,其余季节均无相关性。各季节紫外辐射与能见度无相关性。用总辐射、气温、地表温度、能见度、云量、比湿这些要素分季节建立了估算紫外辐射的方程。做逐步回归时,各季节进入方程的因子不同。对各拟合方程式进行稳定性和可信性检验,其拟合效果较好,方程比较稳定,比较可信,可用来估算紫外辐射值。

The Taklimakan Desert is the largest desert in China.It is particular and typical in all the deserts in China.It affects strongly the climate and entironment in northwest China.Solar ultraviolet radiation including its ecological effect and climatology was observed in recent decades,so it is very important to understand UV radiation in the Taklimakan Desert.Taklimakan Station for Desert Atmospheric Environment Observation and Experiment（39°01′ N,83°40′ E） is located in the hinterland of the Taklimakan Desert.In this paper,the characteristics of solar ultraviolet radiation,affecting factors and their relationships with meteorological factors at the station were analyzed using the data of solar ultraviolet radiation,solar global radiation and some meteorological factors,observed in the hinterland of the Taklimakan Desert during the period from Jane to December 2007.The result shows that the global UV radiation was 305.64 MJ/（m2·a）.The maximum and minimum values of total monthly UV radiation occurred in July and December respectively.The peak value of instantaneous radiant intensity of UV radiation was 67.11 W/m2 and occurred in June.There was a significant correlation between global radiation and UV radiation.The maximum（minimum） ratio of UV radiation to global radiation occurred in summer（winter）.The effect of cloud cover and sand dust on UV radiation was significant.Compared with clear sky,UV radiation was reduced by 31.68% when the total cloud cover was ≥8,and it was reduced by 41.91% when a sandstorm occurred.Judged purely from the annual and daily variation,there were the significant correlations between UV radiation and air temperature and surface temperature,these correlations were stronger in summer than that in winter and stronger at noon than that in the morning or evening.Compared with temperature,there was a good correlation between UV radiation and surface temperature in summer.Water vapor did not directly absorb UV radiation,and there was no correlation between UV radiation and specific humidity except a weak correlation in winter.The factors affecting global radiation,including air temperature,surface temperature,visibility,cloud cover and specific humidity,were used to develop the prediction equations of estimating seasonal UV radiation.The factors used in the stepwise regression equation were different for different seasons.The test revealed that the stability and fitting results were good,and the equations can be used to estimate seasonal UV radiation.