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1. 研究目的与意义及国内外研究现状

湖泊是一种重要的下垫面类型，也是地球气候系统的重要组成部分。全球湖泊和水库面积虽然仅占陆地面积的4%（downing et al., 2006），但是湖泊蒸发对于水资源供给、局地天气、区域气候和流域空气质量影响显著。首先，作为湖泊水循环的主要支出方式，湖泊蒸发直接影响农业灌溉、交通运输、渔业生产、水生生态系统维持以及生活和工业用水的水资源供给（lenters et al., 2004）。其次，作为大气水汽的主要来源，湖泊蒸发能够增强下游降水（samuelsson et al., 2010; zhao et al., 2012），在大型湖泊区域（如北美五大湖区）更为明显。此外，湖泊对局地气温变化具有“缓冲”作用，进而改变局地小气候特征。

与水面蒸发相伴的潜热交换是湖泊能量收支的关键环节，湖泊蒸发通过调节能量收支过程进而改变湖泊与陆地之间的热力差异（long et al., 2007; mackay et al., 2009; balsamo et al., 2012），从而改变诸如湖陆风等局地环流，影响流域污染物的扩散和传输。湖－气之间的潜热通量交换主要受到水体上方的气象要素变化的影响(oswald and rouse et al., 2004)。而天气活动通过改变水体上方气象要素，影响湖泊表面能量收支与平衡(liu et al., 2009; zhang and liu et al., 2013)，比如，干冷空气可以通过增加垂直温度梯度和湿度梯度来促进湖－气之间的感热和潜热通量交换；而暖湿空气通过降低甚至翻转（如逆温和逆湿）垂直温度梯度和湿度梯度来抑制湖－气之间感热通量和潜热通量的交换。并且，寒潮等冷空气活动的入侵会对人类生命和财产造成巨大的损失，因此研究冷空气活动影响下的水面蒸发具有重要的意义。目前对于冷空气活动影响下的水面蒸发的研究主要集中在中高纬地区（如北美五大湖），而对于冷空气影响下的亚热带浅水湖泊的水面蒸发的研究依旧匮乏。

因此，本次选题以亚热带大型浅水湖泊－太湖为研究对象，利用20122013年太湖的涡度相关通量、气象、辐射和水温梯度观测数据，旨在揭示太湖水面蒸发对冷空气以及冷锋过境的响应特征，为太湖流域水资源管理、防灾减灾提供科学依据。

国内外研究现状

2.1 涡度相关法观测湖面蒸发

鉴于湖泊蒸发的社会意义和科学价值，国内外学者通过多种观测手段和模拟技术来衡量水面蒸发速率。观测手段主要包括水分平衡方法、波文比能量平衡法、涡度相关方法（eddy covariance, ec）和大孔径闪烁仪法（winter et al., 1981; 1995），模拟技术主要包括水面蒸发经验模型和湖泊物理机理模型。观测方法中，波文比能量平衡法和涡度相关方法被认为是测量水面蒸发最为准确的方法（winter et al., 1981）。波文比能量平衡法基于能量守恒方程，利用净辐射和热储量观测数据间接计算潜热通量，可能存在误差累计的缺陷。而涡度相关方法具有理论假设少和非破坏性等优点，可用于直接连续观测湖面蒸发潜热（lee et al., 2014）。鉴于涡度相关方法的优越性，国内外学者从上世纪90年代开始采用涡度相关技术来研究湖面蒸发时空变化特征及其影响机制。

2. 研究的基本内容

本文以亚热带大型浅水湖泊—太湖为研究对象，利用20122013年太湖的涡度相关通量、气象、辐射和水温梯度观测数据，旨在揭示太湖水面蒸发对冷空气以及冷锋过境的响应特征，具体研究内容包括：

1)分析20122013年太湖气象因子（温度、水汽压、风）和能量通量（感热通量、潜热通量和净辐射）的时间变化特征；

2） 根据我国现行冷空气等级划分标准，统计20122013年太湖地区冷空气活动的等级和持续时间等。

3)筛选20122013年太湖冷锋过境实例，研究其发生频次、强度和持续时间；

3. 实施方案、进度安排及预期效果

一、实施方案

本文以20122013年太湖的涡度相关通量、气象、辐射和水温梯度观测数据为基础，开展太湖水面蒸发对冷空气以及冷锋过境的响应特征的研究，技术路线图如下：

图1 技术路线图

4. 参考文献

1. Balsamo G, Salgado R, Dutra E, Boussetta S, Stockdale T, Potes M. On the contribution of lakes in predicting near-surface temperature in a global weather forecasting model. Meteorology and Oceanography. 2012, 64: 15829, doi:10.3402/tellusa.v64i0.15829.
2. Bonan Gordon B. Sensitivity of a GCM simulation to inclusion of inland water surfaces. Journal of Climate, 1995, 8(11): 2691–2704. doi:10.1175/1520-0442(1995)0082691:SOAGST2.0.CO;2.
3. Blanken, P.D., Rouse, W.R., Culf, A.D., Spence, C., Boudreau, L.D., Jasper, J.N.,Kochtubajda, B., Schertzer, W.M., Marsh, P., Verseghy, D., 2000. Eddy covariance measurements of evaporation from Great Slave Lake, Northwest Territories, Canada. Water Resources Research, 2000, 36, 1069–1077.
4. Downing, J.A., Y.T. Prairie, J.J. Cole, et al., The global abundance and size distribution of lakes, ponds, and impoundments. Limnology and Oceanography, 2006. 51(5): 2388-2397.
5. Deng, B., Liu, S., Xiao, W., Wang, W., Jin, J., Lee, X. Evaluation of the CLM4 lake model at a large and shallow freshwater lake. Journal of Hydrometeorology. 2013.14 (2), 636–649. doi: http://dx.doi.org/10.1175/JHM-D-12-067.1.
6. Hostetler S W and Bartlein P J 1990 Simulation of lake evaporation with application to modeling lake level variations of Harney–Malheur Lake, Oregon Water Resources Research. 1990, 26, 2603–2612.
7. Jiang, Z., T. Ma, and Z. Wu, China coldwave duration in a warming winter: change of the leading mode. Theoretical and Applied Climatology, 2012. 110(1-2): 65-75. doi: 10.1007/s00704-012-0613-2.
8. Liu,H., Zhang, Y., Liu, S., Jiang,H., Sheng, L.,Williams, Q.L., 2009. Eddy covariance measurements of surface energy budget and evaporation in a cool season over southern open water in Mississippi. Journal of Geophysical Research. 2009. 114, D04110, doi:10.1029/2008JD010891.
9. Liu, H., P. D. Blanken, T. Weidinger, A. Nordbo, and T. Vesala (2011), Variability in cold front activities modulating cool-season evaporation from a southern inland water in the USA, Environmental. Research. Letters., 2011, 6, 024022. doi:10.1088/1748-9326/6/2/024022.
10. Liu, H., Zhang,Q., Dowler,G., 2012. Environmental controls on the surface energy budget over a large southern inland water in the United States: an analysis of one-year eddy covariance flux data. Journal of Hydrometeorol. 2012, 13, 1893–1910. doi: 10.1175/JHM-D-12-020.1
11. Long Z, Perrie W, Gyakum J, Caya D, Laprise R. Northern Lake impacts on local seasonal climate. Journal of Hydrometeorology. 2007, 8: 881–896, doi:10.1175/jhm591.1.
12. M. P. Curtarelli, Modeling the effects of cold front passages on the heat fluxes and thermal structure of a tropical hydroelectric reservoir. Hydrology and Earth System Sciences, 2013, 10 (10):8467-8502. doi:10.5194/hessd-10-8467-2013.
13. MacKay MD, Neale PJ, Arp CD, Domis LND, Fang X, Gal G, Johnk KD, Kirillin G, Lenters JD, Litchman E, MacIntyre S, Marsh P, Melack J, Mooij WM, Peeters F, Quesada A, Schladow SG, Schmid M, Spence C, Stokesr SL. Modeling lakes and reservoirs in the climate system. Limnology and Oceanography. 2009, 54(6,part 2):2315–2329, doi:10.4319/lo.2009.54.6_part_2.2315.
14. Oswald C M and Rouse W R 2004 Thermal characteristics and energy balance of various-size Canadian Shield lakes in the Mackenzie River Basin Journal of Hydrometeorol. 2004, 5 129–144.
15. Samuelsson, P., E. Kourzeneva, and D. Mironov. The impact of lakes on the European climate as simulated by a regional climate model[J]. Boreal Environment Research, 2010, 15(2): 113-129.
16. Winter, T.C. Uncertainties in estimating the water balance of lakes. Water Resources Bulletin, 1981, 17 (1), 82–115.
17. Winter, T.C., Rosenberry, D.O., Sturrock, A.M. Evaluation of 11 equations for determining evaporation for a small lake in north central United States. Water Resources Research, 1995, 31(4), 983–993.
18. Xuhui Lee, Shoudong Liu, Wei Xiao et al., The Taihu Eddy Flux Network: An Observational Program on Energy, Water, and Greenhouse Gas Fluxes of a Large Freshwater Lake. American Meteorological Society, 2014. 95 :140530112919008, doi:10.1175/BAMS-D-I3-00136.1
19. Zhao, L., J.M. Jin, S.Y. Wang, et al. Integration of remote-sensing data with WRF to improve lake-effect precipitation simulations over the Great Lakes region [J]. Journal of Geophysical Research-Atmospheres, 2012. 117: D09102.
20. Zhang, Q., Liu,H., 2013. Interannual variability in the surface energy budget and evaporation over a large southern inland water in the United States. Journal of Geophysical Research-Atmospheres. 2013. 118, 4290–4302. doi:10.1002/jgrd.50435.