基于CLM4.5土壤风蚀模型的河北省土壤释尘量模拟

Simulation of dust emissions in Hebei Province based on CLM4.5 soil wind erosion model

为了定量评价大气污染物中由于土壤风蚀而形成的PM_(10)释放量,基于美国大气研究中心的CLM4.5土壤风蚀模型,运用遥感数据、地面气象监测数据、陆面数据同化系统数据和陆表特征参量产品数据,建立土壤风蚀释尘量的参数体系,模拟2013年河北省的土壤风蚀粉尘中PM_(10)的释尘量。结果表明:2013年河北省PM_(10)的年释尘通量为1.02 t/hm^2,其中,3月份释尘通量最高,为0.28 t/hm^2,占全年释尘量的27.6%,7月份释尘通量最低,仅占全年的0.2%。春季的释尘通量最高,为0.55 t/hm^2,冬季次之,为0.28 t/hm^2,秋季再次之,为0.18 t/hm^2,夏季的释尘通量最低,为0.015 t/hm^2,呈现明显的春高夏低的季节性变化规律。全省土壤风蚀尘中PM_(10)释尘量区域分布差异明显,释尘量最大的区域是沧州滨海平原和坝上高原,其次是冀东滨海平原和冀西北间山盆地。

With the continuous development of the economy and society,the problem of air pollution in China is becoming more and more serious especially in Hebei Province.Currently,Hebei Province has been one of the most serious areas of air pollution in China.The wind-blown dust,emitted from the earth’s surface to the atmosphere,has become one of the main components of air pollutants.The wind-blown dust has significant impacts on atmospheric phenomena and consequently on air quality.The wind-blown dust not only causes atmospheric pollution,but also changes the radiation balance of the ground and the acidity or alkalinity of the aerosol.It not only affects human health but also causes changes in the global climate system and ecosystem.In order to evaluate the PM10 of atmospheric pollutants in Hebei Province caused by wind-blown dust,the article set up parameters system of wind-blown dust production by Community Land Model 4.5(CLM4.5)using remote sensing data,the ground meteorological data,the Land Data Assimilation System data and the land surface characteristic parameters production data with 1 km spatial resolution.The factors affecting the wind-blown dust include soil texture,wind speed,soil moisture,surface roughness,and the proportion of bare soil determined by vegetation coverage,surface freezing ratio,snow cover ratio,lakes and wetland ratio.Wind speed,soil moisture,vegetation coverage,snow cover area and freezing ratio change greatly with the seasons,so they are the sensitive factors of the wind-blown dust.This study provides the first estimates of the fine-scale spatial and temporal distribution of dust emissions from Hebei Province.The result shows that:The wind-blown dust annual emission flux of PM10 is 1.02 t/hm2 in 2013.The highest monthly emission flux is 0.28 t/hm2 in March,accounting for 27.6%of the whole year,and the lowest is July,accounting for only 0.2%.The dust emission flux of spring is 0.55 t/hm2,the summer is 0.015 t/hm2,the autumn is 0.18 t/hm2,and the winter is 0.28 t/hm2.That shows spring is the highest season and summer is the lowest season for wind-blown dust emission flux.There are obvious regional differences about wind-blown dust emissions in Hebei Province,the coastal plain of Cangzhou and Bashang plateau are the highest areas for dust emission flux,annual emission flux of which is 5.365 and 3.542 t/hm2 respectively,and Taihang Mountain piedmont plain is the lowest area,annual emission flux of which is 0.20 t/hm2.The result above shows CLM4.5 wind-blown dust model can well simulate the characteristics of spatial and temporal change in Hebei Province.Comparing the initial data of CLM4.5 with our study data,it presents the spatial resolution of initial data is very low,and not suitable for the simulation of the small area,in contrast,the local parameters we used including vegetation coverage,wind speed,soil moisture,the proportion of bare soil,lakes and wetland ratio data with high spatial resolution(1 km)have improved the accuracy of the simulation result.This paper is not only meaningful for evaluating the PM10 from wind-blown dust in Hebei Province,but also the first application to estimate wind-blown dust in the fine scale by CLM4.5 model.