青藏高原林芝与四川盆地温江地区晴天辐射和能量平衡特征

Radiation and Surface Energy Balance Characteristics during Clear Days in Nyingchi(Tibet) and Wenjiang(Sichuan)

分析了2008年青藏高原林芝地区与四川盆地温江地区无降水条件下地表辐射、湍流通量和地表反照率的日变化及月际变化特征,并探讨了季风过程对其产生的影响.结果表明:林芝与温江地区地表辐射和湍流通量都具有明显的日变化和月际变化周期,季风期受云的影响,日循环规律变得不是非常规则.季风对林芝地区地表能量分配影响极大,季风前感热通量占主导地位,季风期和季风后(夏、秋节)潜热通量是净辐射的主要消耗项;温江地区全年潜热在净辐射的分布中占主导地位,感热通量的作用和土壤热通量相当.林芝地区年平均地表反照率为0.21,温江地区年平均仅为0.14;季风前(3-5月)、季风中(6-7月)和季风后(8-9月),林芝地区的地表反照率分别为0.20、0.19和0.20,温江地区的地表反照率分别为0.13、0.11和0.14.

The diurnal and monthly variations of land surface radiation fluxes,turbulent heat fluxes and albedo over Nyingchi Prefecture and Wenjiang District are investigated based on the radiation and turbulent flux data measured with radiometer and Eddy Covariance method in 2008.The influence of monsoon on the radiation fluxes,turbulent heat fluxes and albedo are also discussed.It is found that there are distinct diurnal and monthly variations of radiation fluxes and components of surface heat flux over Nyingchi Prefecture and Wenjiang District.During monsoon season,the influence of cloud on the surface radiation flux and turbulent heat flux results in daily circulation irregular.Monsoon has a significant influence on the ratio of net radiation to sensible and latent heat fluxes in Nyingchi Prefecture.The ratio to sensible heat flux is higher than that to latent heat flux in pre-monsoon season（April-May）.In monsoon season（June-July） and post-monsoon period（August-September）,the ratio to latent heat flux is higher than that to sensible heat flux.However,in Wenjiang District the ratio of net radiation to latent heat flux is the annual maximum,and that to sensible heat fluxes is nearly equal to that to soil heat flux.The annual mean albedo is 0.21 in Nyingchi Prefecture and 0.14 in Wenjiang District.The albedo is 0.20,0.19 and 0.20 on Nyingchi Prefecture and 0.13,0.11 and 0.14 on Wenjiang District before monsoon,during monsoon and after monsoon,respectively.