Lake Fluctuation Effectively Regulates Wetland Evapotranspiration: A Case Study of the Largest Freshwater Lake in China

Water

Xiaosong Zhao¹ 

[1] State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; E-Mail

关键词: evapotranspiration;    Poyang Lake wetland;    water level;    remote sensing;   

DOI  :  10.3390/w6082482

来源: mdpi

【 摘 要 】

Lakes and wetlands provide valuable water resources. Wetland evapotranspiration (ET) is a key hydrologic component; however, the effects of lake fluctuation on wetland ET remain unclear. The Poyang Lake is the largest freshwater lake in China and experiences a dramatic fluctuation in water level and inundated area. This study used remote sensing data to estimate the wetland ET for Poyang Lake and to illustrate the distribution of wetland ET and its response to lake fluctuations. Our results showed that wetland ET was related to lake fluctuation both spatially and temporally. Within the same year, the difference between annual water evaporation (E_water) and wetland ET (ET_wetland) was primarily attributed to lake fluctuation through its effects on inundated area and exposure days. A 1% increase in inundated area would result in a 7.87 ± 1.13 mm a⁻¹ reduction in annual E_water-to-ET_wetland differences, and a 10-day elongation of exposure could lead to an 11.1 ± 1.6 mm a⁻¹ increase in annual E_water-to-ET_wetland differences, on average. Inter-annually, the E_water-to-ET_wetland differences were attributed to the combined effects of atmospheric and environmental variables and lake fluctuation. The lake fluctuation contributed 73% to the inter-annual ET difference, followed by relative humidity (19%), net radiation (5%), and wind speed (4%). Overall, lake fluctuation effectively regulates wetland ET, and its effect should receive careful consideration in hydrological and water resources studies under the current changing climate.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.