海陆界面水汽输送对辽河三角洲区域参考蒸散发的影响

Influence of the Sea-land Interface Moisture Transport Flux on Reference Evapotranspiration in Liaohe Delta

海陆界面水汽输送/交换及其区域蒸散发对海岸生态系统演化具有十分重要的影响.利用NCEP/NCAR再分析数据和气象观测数据,定量分析辽河三角洲地区海陆界面水汽输送通量的时空特征及对参考蒸散发(ET0)的影响,结果显示,海陆界面水汽输送通量与东亚气候系统联系紧密,具有明显的季节差异,夏季高、冬季低,呈单峰分布.在月尺度上水汽通量与ET0整体呈显著正相关:春季和秋季水汽通量更多的表现出纬向水汽输送的特征,与ET0显著正相关;夏季经向水汽通量(南风输送)在海陆界面水汽输送中的比重增加,呈显著负相关;冬季则不显著.多项式曲线拟合结果表明,随着水汽通量的增加,ET0相应增大,当水汽通量达到一定阈值(67～75kg/(m.s))后,ET0随水汽通量的增大而减小.分层计算结果表明当海陆水汽通量与ET0正相关时(春季和秋季),地面-850hPa层的贡献最大;当负相关时(夏季),700～300hPa层的贡献最大.

As the part of the global atmospheric circulation, the sea-land moisture transport plays an im- portant role on the land surface water and energy balance, as same to the regional hydrology cycle, ecology and climate. In this paper, the temporal-spatial variation of the sea-land boundary＇s moisture transport flux in the northern of Liaodong Bay, Bohai Sea, derived from NCAR/NCEP reanalysis dataset for 1971-- 2010, was characterized quantitatively. Moreover, the relationship between the sea-land interface moisture transport flux and reference evapotranspiration of Liaohe Delta has been analyzed using a set of statistical approaches. Reference evapotranspiration was calculated using locaI land-surface daily meteorological data. The result shows that sea-land interface moisture transport flux has a apparently seasonal variation, with the highest value in summer and lowest in winter, presenting a single-peak curve pattern. At monthly time scale, the sea-land interface moisture transport flux is overall significantly positively corrected with refer- ence evapotranspiration in all 10 stations. Furthermore, it shows significant positive correction in spring and fall, and significantly negative correction in summer, and no correction in winter. It may be caused by changing direction and rate of the zonal moisture transport flux and meridional moisture transport flux in different seasons, mainly driven by the East Asian Mosoon and Northern Hemisphere Westerlies. Regres- sion between the sea-land moisture transport flux and reference evapotranspiration has been established ap- plying the polynomial curve fitting technique. The curves demonstrate that reference evapotranspiration increases with the increase of sea-land moisture transport flux, and the opposite trend appears until the sea-land moisture transport flux exceeds the threshold （67--75 kg/ms）. In addition, correlation analysis of the layered sea-land moisture transport flux and reference evapotranspiration reveals that the layered flux within surface pressure-850 hPa layer has more affect on reference evapotranspiration in spring and fall, on the contrary the layered flux within 300--700 hPa layer has more affect in summer.