Impacts of meteorological nudging on the global dust cycle simulated by NICAM coupled with an aerosol model
Impacts of meteorological nudging on the global dust cycle simulated by NICAM coupled with an aerosol model
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NICAM 与气溶胶模型相结合模拟气象推动对全球沙尘循环的影响
DOI：
10.1016/j.atmosenv.2018.07.016
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发表时间：
2018
影响因子：
5
通讯作者：
Nakajima Teruyuki
中科院分区：
文献类型：
--
作者：
Dai Tie;Cheng Yueming;Zhang Peng;Shi Guangyu;Sekiguchi Miho;Suzuki Kentaroh;Goto Daisuke;Nakajima Teruyuki
在这项研究中，我们使用基于非静水二十面体大气模型（NICAM）和气溶胶物种光谱辐射传输模型（SPRINTARS）的新尘埃大气模型对当今条件下的全球尘埃循环进行了模拟。我们重点评估粉尘模拟的排放、沉积、表面浓度、气溶胶光学深度 (AOD) 和粉尘-气溶胶直接辐射效应 (DRE)。还通过有和没有气象助推来研究沙尘模拟对气象场的敏感性。没有气象助推的 NICAM 往往会系统性地高估 10m 风速约 30%–40%，而通过气象助推，10m 风速的每日震级和变化都得到显着改善，尤其是在撒哈拉沙漠。在气象推动下，估计的全球年平均粉尘排放通量、粉尘 AOD 和大气顶部粉尘-气溶胶短波 DRE 分别为 1463Tgyr−1、0.033 和 −1.3 Wm-2。由于两大沙漠地区10m风速高估约30%~40%，无气象助推的全球年平均沙尘排放通量、AOD和DRE的估计值显着大于有气象助推的情况。 10m风速和相关扬尘排放的高估主要是由于风速的正偏差，特别是从地面到2km左右的风速的正偏差造成的，并且受温度场的影响较小。通过气象推动，可以更好地模拟大西洋上空灰尘沉积量和太平洋上空表面灰尘浓度的每月变化。与 AERONET（气溶胶机器人网络）和 MODIS（中分辨率成像光谱仪）检索的 AOD 相比，模拟的每日 AOD 变化在气象推动下显着改善，特别是在沙尘气溶胶占主导地位的地区。全球和年平均尘埃寿命和尺寸分布是估计尘埃辐射效应的两个关键因素，动态和微动NICAM之间非常相似。因此，我们可以使用动态模型来了解全球和年度范围内的气候与灰尘的相互作用。此外，我们可以通过气象推动来提高区域和季节尺度上某些应用的模型性能，这可能无法通过仅调整粉尘排放来实现。
In this study, we present simulations of the global dust cycle for present day conditions using a new dust-atmosphere model based on the Non-hydrostatic Icosahedral Atmospheric Model (NICAM) coupled with the Spectral Radiation Transport Model for Aerosol Species (SPRINTARS). We focus on evaluations of the dust simulation with respect to emissions, depositions, surface concentrations, aerosol optical depths (AODs), and the dust-aerosol direct radiative effects (DREs). The sensitivities of the dust simulation to the meteorological fields are also investigated through with and without meteorological nudging. NICAM without meteorology nudging tends to systemically overestimate the 10 m wind speeds by approximately 30%–40%, whereas the daily magnitudes and variations in the 10 m wind speeds are both significantly improved with meteorological nudging, especially over the Sahara Desert. The estimated annual global mean dust emission flux, dust AOD, and dust-aerosol shortwave DRE at the top of the atmosphere with meteorological nudging are 1463 Tg yr−1, 0.033, and −1.3 Wm-2, respectively. Due to the approximately 30%–40% overestimations of the 10 m wind speeds over the two major desert regions, the estimated annual global mean dust emission flux, AOD, and DRE without meteorological nudging are significantly greater than those with meteorological nudging. The overestimations of 10 m wind speeds and the associated dust emissions are mainly caused by the positive biases of wind speeds especially from surface to approximately 2 km and slightly affected by the temperature fields. The monthly variations in the dust depositions over the Atlantic and the surface dust concentrations over the Pacific are all better simulated with meteorological nudging. Compared to both the AERONET (Aerosol Robotics Network)- and MODIS (Moderate-Resolution Imaging Spectroradiometer)- retrieved AODs, the simulated daily AOD variations are significantly improved with meteorological nudging, especially over the dust-aerosol dominated regions. The global and annual mean dust lifetime and size distribution, which are two critical factors for estimating dust radiative effects, are quite similar between the dynamic and nudged NICAMs. We therefore can use the dynamic model to understand climate-dust interactions in a global and annual scale. Furthermore, we can improve the model performances for some applications in regional and seasonal scales by meteorological nudging which probably cannot be achieved by just tuning the dust emission.