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| 湖泊过程影响局地天气和气候的数值模拟 | |
| 其他题名 | The Simulation of the Impact of Lake Process on the Regional Weather and Climate |
| 赵林 | |
| 出版年 | 2012 |
| 学位类型 | 博士 |
| 导师 | 吕世华 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 本文分别利用中尺度大气模式WRF3.2以及耦合了CLM 3.5陆面过程模块（含湖泊陆面过程模块）的WRF-CLM，主要模拟讨论湖泊陆面过程对局地天气和气候的影响。本文主要研究对象为美国五大湖和大盐湖，模拟分析了冬季湖泊温度和湖冰对湖泊效应降水的影响、夏季典型晴天湖泊对局地环流的影响以及湖泊在弓形回波强对流天气过程中所起的作用，同时也对比分析了国内巴丹吉林地区不同下垫面（沙漠和湖泊）辐射能量收支状况。结果主要如下：\n 1. 通过数值模拟试验，初步对比分析WRF模式模拟的沙漠和湖泊不同下垫面的辐射收支情况, 结果表明近地层的温度梯度对感热和潜热通量输送有着重要影响。这也说明湖泊表面温度对于模拟湖泊陆面对局地天气和气候的重要性，这对后面章节湖泊效应数值模拟工作的开展有一定的指导意义。另外，WRF模式的模拟区域包含湖泊时，海表温度（SST）更新选项需启用，否则会导致湖泊表面温度恒定不变，影响模式的辐射能量收支模拟效果，进一步会影响到局地的天气和气候。\n 2. 利用遥感观测MODIS获取的湖泊表面温度和美国冰面研究中心（NIC）的冰分布数据，将其加入到WRF-CLM模式中以检验湖泊边界条件（湖泊表面温度和冰）对美国大湖区湖泊效应降水模拟的影响。通过加入和不加入MODIS湖泊温度和NIC湖泊冰分布资料的对比试验，检验二者对湖泊效应降水模拟的影响。研究结果表明，相对更真实的 MODIS湖温和NIC冰分布的加入会减少模式在湖面模拟的过多的感热和潜热通量，从而显著改进模式对湖泊效应降水的模拟效果。通过进一步对11个湖泊效应降水个例的合成分析发现，MODIS湖温和NIC冰分布资料的加入使模式更真实的模拟了湖面低层大气的稳定性状况和水汽传输，因而改进了模拟的湖泊效应降水。 \n 3. 利用WRF-CLM对春季大盐湖区域的一次罕见弓形回波强对流性天气进行了数值模拟研究。北美中尺度预报模式NAM并不能预报出此次天气过程。而WRF模式，将模式分辨率提高到1 km分辨率以后，模式具备模拟弓形回波的能力，但多组云微物理参数化方案敏感性试验的结果表明，WRF模式模拟的降水普遍滞后1-2小时。分析发现，（1）模式模拟降水滞后的可能原因是模式模拟槽的移动速度较观测资料偏慢；（2）此次天气过程主要是由于天气尺度的短波槽中发展了此天气尺度的扰动所引起，湖泊对此次天气过程所引起的降水不显著。\n 4. 在夏季典型晴天条件下，有无启用湖泊陆面过程时，WRF-CLM基本都能模拟出Michigan湖和Huron湖的湖陆风特征。分析发现，此次湖风可能主要是动力作用产生，即由于高空下沉气流和水面和陆地粗糙度的差异所引起。而Michigan湖和Huron湖模拟温度相对偏高，是由于含一维热扩散湖泊陆面过程的WRF-CLM模式中，热扩散系数的均一设置所导致。\n \n关键词： WRF模式；WRF-CLM模式；湖泊陆面过程；MODIS湖泊表面温度；NIC冰的分布；湖陆风；湖泊效应降水；沙漠；辐射通量。 |
| 英文摘要 | Using the Advanced Research Weather Research and Forecasting (WRF) model version 3.2 and the coupled WRF and the Community Land Model version 3.5 (WRF-CLM), this study investigated the impact of lake surface process on regional weather and climate over the Great Lakes region. The impact of lake ice and lake surface temperature on lake effect precipitation in winter, lake-land breeze in summer, and the impact of lake on the bow echo development have been explored. Meanwhile, the feature of radiation components over different land-use type has also been investigated. Some conclusions are as follows: \n(1) Based on simulations, energy balance over different land-use types (i.e., lake and desert) has been investigated. The results shows, temperature gradient over surface layer has a significant effect on sensible heat flux and latent heat flux. On the other hand, if the simulation domain including landuse of lake, SST update option should be adopted to simulate reasonable lake surface temperature, which further affect local the weather and climate.\n(2) Remotely sensed lake surface temperature (LST) and lake ice cover (LIC) were integrated into the Advanced Research Weather Research and Forecasting (WRF) model version 3.2 to evaluate the simulation of lake-effect precipitation over the Great Lakes region. The LST was derived from the Moderate Resolution Imaging Spectroradiometer (MODIS), while the LIC was obtained from the National Ice Center (NIC). WRF simulations for the Great Lakes region were performed at 10 km grid spacing for the cold season from November 2003 through February 2008. Initial and lateral boundary conditions were provided by the North American Regional Reanalysis (NARR). Experiments were carried out to compare winter precipitation simulations with and without the integration of the satellite data. Results show that integration with MODIS LST and NIC LIC significantly improves simulation of lake-effect precipitation over the Great Lakes region by reduced latent heat flux. A composite analysis of lake-effect precipitation events further reveals that more accurately depicted low-level stability and vertical moisture transport forced by the observation-based LST and LIC contribute to the improved simulation of lake-effect precipitation.\n(3) A rare springtime bow echo occurred in arid northern Utah over the desert region of the GSL. A number of experiments using the ARW model were conducted, and NAM forecasts along with RUC analyses were also examined. The NAM forecast failed to capture this event. Comparing 5- and 1-km simulations, the 1-km run produced finer-scale convective features with more realistic structures than the 5-km run. All of the experiments simulated the bow echo about 1 to 2 hours too late. Comparison between no-lake and control simulations suggests that the GSL did not have a noticeable impact on the bow echo development. It is therefore concluded that the bias of NAM (and ARW) in simulating the propagation of the midtropospheric disturbance is likely to be a significant obstacle in forecasting this event. Further research is needed to resolve the propagation speed bias of bow echo simulations.\n(4) The ability of the coupled WRF-CLM to simulate lake-land breeze were examined. Generally, both experiments, which adopted and not adopted the shceme of lake surface process, reproduced the feature of lake breeze. The results show that the main reason for this lake breeze may cause by the upper level downdraft and the surface roughness difference between lake and land, but not the lake-land temperature difference. On the other hand, the uniform setting of thermal diffusion parameterization in the lake model may generate higher air temperature by WRF-CLM in deep lake, which should be various in lakes of different depth. \n \nKey Words: WRF model; lake model; MOIDS lake surface temperature; NIC ice fraction; lake-land breeze; lake effect precipitation; desert; radiation flux. |
| 中文关键词 | WRF模式 ; 湖陆风 ; 湖泊效应降水 |
| 英文关键词 | WRF model lake-land breeze lake effect precipitation |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 大气物理学与大气环境 |
| 来源机构 | 中国科学院西北生态环境资源研究院 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/287088 |
| 推荐引用方式 GB/T 7714 | 赵林. 湖泊过程影响局地天气和气候的数值模拟[D]. 中国科学院大学,2012. |
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