Evaluating the skill of high-resolution WRF-Chem simulations in describing drivers of aerosol direct climate forcing on the regional scale
Evaluating the skill of high-resolution WRF-Chem simulations in describing drivers of aerosol direct climate forcing on the regional scale
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DOI：
10.5194/acp-16-397-2016
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发表时间：
2016-01-01
影响因子：
6.3
通讯作者：
Pryor, S. C.
中科院分区：
文献类型：
--
作者：
Crippa, P.;Sullivan, R. C.;Pryor, S. C.
评估全球和区域模式描述气溶胶光学性质的能力对于减少当代气候中气溶胶直接辐射强迫的不确定性和提高对未来预测的信心至关重要。在这里，我们通过与地面和空间遥感观测的比较，评估了使用天气研究和预报模式与化学耦合(WRF-CHEM)进行的高分辨率模拟在捕捉气溶胶光学厚度(AOD)和Angstrom指数(AE)的时空变化方面的性能。WRF-Chem以12公里的分辨率在北美东部运行，为期一年(2008年)。模拟的AOD相对于观测值存在系统的正偏差(相对于MODIS(中分辨率成像光谱仪)和AERONET，年平均分数偏差(MFB)分别为0.15和0.50)，而大部分月份的空间变异性被很好地捕捉到。观测和模拟的气溶胶光学厚度的空间相关性表现出明显的季节变化周期，相关系数在夏季最高(r=0.5-0.7)，此时气溶胶负荷较大，观测资料较多。该模式偏向于粗模气溶胶的模拟(相对于MODIS和AERONET，每年的AE的MFB=-0.10和-0.59)，但在大多数月份中，AE与观测值的空间相关性为0.3-0.5，尽管从遥感观测中反演AE的不确定性较高。WRF-Chem在识别极端和非极端气溶胶负荷区域方面也表现出很高的技能，其正确模拟极端气溶胶事件(即AOD>；75%百分位数)的位置和相对强度的能力在冬季和夏季分别在30%和70%之间变化。
Assessing the ability of global and regional models to describe aerosol optical properties is essential to reducing uncertainty in aerosol direct radiative forcing in the contemporary climate and to improving confidence in future projections. Here we evaluate the performance of highresolution simulations conducted using the Weather Research and Forecasting model with coupled with Chemistry (WRF-Chem) in capturing spatiotemporal variability of aerosol optical depth (AOD) and the Angstrom exponent (AE) by comparison with ground- and space-based remotely sensed observations. WRF-Chem is run over eastern North America at a resolution of 12 km for a representative year (2008). A systematic positive bias in simulated AOD relative to observations is found (annual mean fractional bias (MFB) is 0.15 and 0.50 relative to MODIS (MODerate resolution Imaging Spectroradiometer) and AERONET, respectively), whereas the spatial variability is well captured during most months. The spatial correlation of observed and simulated AOD shows a clear seasonal cycle with highest correlation during summer months (r = 0.5-0.7) when the aerosol loading is large and more observations are available. The model is biased towards the simulation of coarse-mode aerosols (annual MFB for AE = -0.10 relative to MODIS and -0.59 for AERONET), but the spatial correlation for AE with observations is 0.3-0.5 during most months, despite the fact that AE is retrieved with higher uncertainty from the remotesensing observations. WRF-Chem also exhibits high skill in identifying areas of extreme and non-extreme aerosol load-ing, and its ability to correctly simulate the location and relative intensity of extreme aerosol events (i.e., AOD > 75th percentile) varies between 30 and 70% during winter and summer months, respectively.