Water and energy budgets of hurricanes: Case studies of Ivan and Katrina
Water and energy budgets of hurricanes: Case studies of Ivan and Katrina
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DOI：
10.1029/2006jd008303
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发表时间：
2007-12
影响因子：
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通讯作者：
K. Trenberth;C. Davis;J. Fasullo
中科院分区：
文献类型：
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作者：
K. Trenberth;C. Davis;J. Fasullo
[1]为了探讨飓风在气候系统中的作用，对2004年9月伊万和2005年8月卡特里娜飓风的总体大气湿度收支进行了详细的分析。风暴中超过20 mm h−1的强降水大大超过地面蒸发水汽通量，大气最低1公里水汽的垂直积分辐合是水汽收支中的主导项，突出了大尺度环境的重要性。还对卡特里娜飓风的情况进行了模拟，作为敏感性研究，海面温度(SST)增加了+1°C，−下降了1°C。在模拟开始后的42到54小时内，热带海温每增加1°C，最大地面风速增加约4.5m S−1(9%)，海平面气压下降11.5hpa。总体而言，随着海温的增加，飓风的规模扩大，环境大气水汽在接近克劳修斯-克拉珀龙方程的6%K−1附近增加，地表水汽通量也主要由于克劳修斯-克拉佩龙效应和风暴强度的变化而增加。1970年以来与人类影响气候有关的环境变化增加了海温和水汽，结果表明这可能改变了飓风并增加了相关的风暴降雨量，后者迄今被量化为6%至8%左右。
[1] To explore the role of hurricanes in the climate system, a detailed analysis is made of the bulk atmospheric moisture budget of Ivan in September 2004 and Katrina in August 2005 from simulations with the Weather and Research Forecasting (WRF) model at 4 km resolution without parameterized convection. Heavy precipitation exceeding 20 mm h−1 in the storms greatly exceeds the surface flux of moisture through evaporation, and vertically integrated convergence of moisture in the lowest 1 km of the atmosphere from distances up to 1600 km is the dominant term in the moisture budget, highlighting the importance of the larger-scale environment. Simulations are also run for the Katrina case with sea surface temperatures (SSTs) increased by +1°C and decreased by −1°C as sensitivity studies. For hours 42 to 54 after the start of the simulation, maximum surface winds increased about 4.5 m s−1 (9%), and sea level pressure fell 11.5 hPa per 1°C increase in tropical SSTs. Overall, the hurricane expands in size as SSTs increase, the environmental atmospheric moisture increases at close to the Clausius-Clapeyron equation value of about 6% K−1 and the surface moisture flux also increases mainly from Clausius-Clapeyron effects and the changes in intensity of the storm. The environmental changes related to human influences on climate since 1970 have increased SSTs and water vapor, and the results suggest how this may have altered hurricanes and increased associated storm rainfalls, with the latter quantified to date to be of order 6 to 8%.