The CCSM4 Land Simulation, 1850-2005: Assessment of Surface Climate and New Capabilities
The CCSM4 Land Simulation, 1850-2005: Assessment of Surface Climate and New Capabilities
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DOI：
10.1175/jcli-d-11-00103.1
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发表时间：
2012-04-01
影响因子：
4.9
通讯作者：
Bonan, Gordon B.
中科院分区：
文献类型：
--
作者：
Lawrence, David M.;Oleson, Keith W.;Bonan, Gordon B.
本文回顾了社区陆地模式第四版(CLM4)的发展，比较了社区气候系统模式第四版(CCSM4)与CCSM3的陆面气候模拟，并评估了CCSM4中CLM4的新的地球系统特征。CLM4包含了一系列广泛的改进，包括添加了碳-氮(CN)生物地球化学模型、城市峡谷模型、土地覆盖和土地利用的瞬变变化以及修正的土壤和雪子模型。在离线CLM4模拟中明显的土壤水储存、蒸散、地表反照率和永久冻土模拟方面的改进通常保留在CCSM4中。在许多地方，特别是在高纬度地区，全球陆地气温偏差减少，年循环得到改善。全球陆地降水偏差在CCSM4中较大，因为在中南部非洲和澳大利亚有较大的湿偏差。今天城市地区的气温比周围农村地区高1摄氏度-2摄氏度，这与过去130年来发生的气候变化相当或更大。雪的反照率反馈更接近实际，计算出的雪气溶胶沉降的辐射强迫为+0.083 Wm(-2)。在历史模拟的大部分时间里，由于土地利用、野火和净生态系统生产而产生的陆地碳通量是大气的碳源。CCSM4越来越适合于研究土地过程在气候和气候变化中的作用。
This paper reviews developments for the Community Land Model, version 4 (CLM4), examines the land surface climate simulation of the Community Climate System Model, version 4 (CCSM4) compared to CCSM3, and assesses new earth system features of CLM4 within CCSM4. CLM4 incorporates a broad set of improvements including additions of a carbon-nitrogen (CN) biogeochemical model, an urban canyon model, and transient land cover and land use change, as well as revised soil and snow submodels.Several aspects of the surface climate simulation are improved in CCSM4. Improvements in the simulation of soil water storage, evapotranspiration, surface albedo, and permafrost that are apparent in offline CLM4 simulations are generally retained in CCSM4. The global land air temperature bias is reduced and the annual cycle is improved in many locations, especially at high latitudes. The global land precipitation bias is larger in CCSM4 because of bigger wet biases in central and southern Africa and Australia.New earth system capabilities are assessed. The present-day air temperature within urban areas is warmer than surrounding rural areas by 1 degrees-2 degrees C, which is comparable to or greater than the change in climate occurring over the last 130 years. The snow albedo feedback is more realistic and the radiative forcing of snow aerosol deposition is calculated as +0.083 W m(-2) for present day. The land carbon flux due to land use, wildfire, and net ecosystem production is a source of carbon to the atmosphere throughout most of the historical simulation. CCSM4 is increasingly suited for studies of the role of land processes in climate and climate change.