中国区临近空间太阳辐射环境研究

Radiation Environment Study of Near Space in China Area

临近空间（20~50km）航空活动是全世界航空大国竞相研究的热点。太阳辐射环境研究是开展该高度层航空活动的必要前提,然而临近空间辐射观测资料空白对其开发利用造成了障碍。臭氧是影响高空辐射环境的关键因子,基于欧洲中尺度预报中心再分析资料对中国区临近空间臭氧的空间分布、季节变化特征进行了分析,发现其时空分布及演变具备区域性特点,同时根据平流层大气数据及地表特征等将中国临近空间划分为5个区域,确定不同区域关键参数值,利用SBDART辐射传输模型对临近空间全波段太阳辐射及紫外辐射分别进行模拟。模拟结果显示受纬度、臭氧总量、垂直分布等影响,辐射值变化规律较为复杂。全波段太阳辐射年均和逐月值随纬度降低而增大,年较差则相反;大气的吸收作用与纬度、海陆差异有关,表现出不同的强度和季节变化特征;在紫外波段,南海上空辐射最强,年较差小,月较差很小且夏强冬弱,其他区域辐射值夏强冬弱,月较差呈双峰特征,春秋强,冬夏弱;大气的吸收作用受多因子影响,除南海外,各区域夏季辐射垂向差异更大;大气吸收引起的月较差垂向变化均表现为6、7月高低空月振幅一致,其它月份辐射值在高层月较差更大。

Aerospace activity in near space（20~50km）has become a research hotspot for aviation big countries worldwide.Solar radiation study,as the prerequisite to carry out aerospace activity,is facing the barrier of lacking of observation in near space layer.Ozone is the most important factor that affects radiation value in this layer.Based on ECMWF reanalysis data,this input key parameter and its horizontal,vertical and temporal characteristics are analyzedwith results showing obvious regional features in temporal-spatial distribution and varieties.With meteorological data and surface parameters,near space over China is divided into 5parts.Key factors＇ value is confirmed over each division.With SBDART radiation transfer model,solar radiation and ultraviolet radiation simulation in near space are conducted separately.Results show that it is influenced by latitude,total ozone and its vertical distribution,radiation varies under complex rules.The average year and monthly solar radiation strengthens changes with latitude reduction,while annual range changes reversely.Air absorbing is related to latitude and land-sea contrast and shows different values and seasonal variations.The ultraviolet radiation over South China Sea reaches its maximum value and minimum annual range,as well as minimum monthly range with value strengthening in summer and weakening in winter.In other areas radiation increases in summer while weakens in winter,monthly range shows double peaks with higher value in spring and autumn,lower in summer and winter.Air absorption in ultraviolet radiation is influenced by multiple factors,vertical varieties over areas besides South China Sea enhance in summer time.The vertical changes of monthly ranges affected by air absorption show consistence in higher and lower layer in June and July,while in other months ranges are bigger in higher layer.