Temporal variation of reference evapotranspiration during 1961-2005 in the Taoer River basin of Northeast China

Evapotranspiration is an important flux term in the water cycle that integrates atmospheric demands and surface conditions. Thus, analysis of the temporal variation of reference evapotranspiration (ET0) will help us to understand climate change and its effect on hydrology. In this paper, we present an analysis of the monthly ET0 at 15 stations during 1961–2005 in the Taoer River basin in China, calculated by the FAO Penman–Monteith method. We derived the growing season and annual total ET0 time series and using the Mann–Kendall method, moving t test and Morlet wavelet conducted comprehensive time series analysis to characterize significance test, abrupt change and period in the ET0 data sets. The results present that: (i) in terms of the seasonal cycle, monthly ET0 reaches its peak in May and growing season ET0 accounts for 60.7% of annual total. Long term growing season ET0 fluctuates in accordance with annual ET0, both having turning points in 1982 and 1993; (ii) with respect to the long term persistence, the trends for growing season and annual ET0 show the same spatial patterns: high positive values in the west study area in the upper reach and negative values in the Southeast study area in the lower reach. The spatial distribution of annual tendencies suggests an influence from the altitude and latitude; (iii) for individual station, abrupt changes in annual ET0 are more pronounced than those in growing season ET0. The timings for the abrupt changes in ET0 series at individual stations are consistent with those in regional ET0. Abrupt changes detected in the early 1980s are all increasing changes, while those in earlier 1990 are all decreasing changes; and (iv) based on the Morlet wavelet analysis, there exist significant periods of 1, 3 and 7.3 years in annual ET0 series and significant 1 year period and 7.3 years period in growing season ET0 series. Maximum air temperature, mean air temperature, relative humidity and bright sunshine hours are main climate variables responsible for the periodicity in ET0.

[1]  T. McVicar,et al.  Wind speed climatology and trends for Australia, 1975–2006: Capturing the stilling phenomenon and comparison with near‐surface reanalysis output , 2008 .

[2]  Chong-Yu Xu,et al.  Observed trends of annual maximum water level and streamflow during past 130 years in the Yangtze River basin, China , 2006 .

[3]  Xingguo Mo,et al.  Simulating temporal and spatial variation of evapotranspiration over the Lushi basin , 2004 .

[4]  Baryohay Davidoff,et al.  Comparison of Some Reference Evapotranspiration Equations for California , 2005 .

[5]  Liao Jing.  Comparison and Analysis on the Performance of Hydrological Time Series Change-point Testing Methods , 2007 .

[6]  A. Serrano,et al.  Trend analysis of monthly precipitation over the iberian peninsula for the period 1921–1995 , 1999 .

[7]  M. Roderick,et al.  Pan Evaporation Trends and the Terrestrial Water Balance. II. Energy Balance and Interpretation , 2009 .

[8]  W. Gonzalez,et al.  Solar variability effects studied by tree-ring data wavelet analysis , 2002 .

[9]  Thomas C. Brown,et al.  Observational evidence of the complementary relationship in regional evaporation lends strong support for Bouchet's hypothesis , 2005 .

[10]  Terry A. Howell,et al.  Conversion between evapotranspiration references and methods. , 2000 .

[11]  Chong-Yu Xu,et al.  Sensitivity of the Penman–Monteith reference evapotranspiration to key climatic variables in the Changjiang (Yangtze River) basin , 2006 .

[12]  D. Rayner,et al.  Wind Run Changes: The Dominant Factor Affecting Pan Evaporation Trends in Australia , 2007 .

[13]  Tarek El-Ghazawi,et al.  Rain gauge derived precipitation variability over Virginia and its relation with the El Nino southern oscillation , 2004 .

[14]  L. S. Pereira,et al.  Crop evapotranspiration : guidelines for computing crop water requirements , 1998 .

[15]  Tim R. McVicar,et al.  Spatially distributing monthly reference evapotranspiration and pan evaporation considering topographic influences , 2007 .

[16]  M. Kendall.  Rank Correlation Methods , 1949 .

[17]  Jiang Fengqing.  A Study of Abrupt Climate Change in Xinjiang Region during 1961—2004 , 2007 .

[18]  Thomas C. Brown,et al.  Trends in pan evaporation and actual evapotranspiration across the conterminous U.S.: Paradoxical or complementary? , 2004 .

[19]  Pao-Shan Yu,et al.  Impact of climate change on water resources in southern Taiwan , 2002 .

[20]  C. Torrence,et al.  A Practical Guide to Wavelet Analysis. , 1998 .

[21]  Donald H. Burn,et al.  Trends and variability in the hydrological regime of the Mackenzie River Basin , 2006 .

[22]  M. Roderick,et al.  Pan Evaporation Trends and the Terrestrial Water Balance. I. Principles and Observations , 2009 .

[23]  M. Roderick,et al.  The cause of decreased pan evaporation over the past 50 years. , 2002, Science.

[24]  Mike Hulme,et al.  Evaporation and potential evapotranspiration in India under conditions of recent and future climate change , 1997 .

[25]  Bin Li,et al.  Sensitivity of penman-monteith reference crop evapotranspiration in Tao’er River Basin of northeastern China , 2008 .

[26]  Lijuan Li,et al.  Assessing the impact of climate variability and human activities on streamflow from the Wuding River basin in China , 2007 .

[27]  M. Farge.  Wavelet Transforms and their Applications to Turbulence , 1992 .

[28]  Khaled H. Hamed.  Trend detection in hydrologic data: The Mann–Kendall trend test under the scaling hypothesis , 2008 .

[29]  T. Jiang,et al.  Analysis of spatial distribution and temporal trend of reference evapotranspiration and pan evaporation in Changjiang (Yangtze River) catchment , 2006 .

[30]  Branimir Todorovic,et al.  Forecasting of Reference Evapotranspiration by Artificial Neural Networks , 2003 .

[31]  T. McVicar,et al.  Developing a decision support tool for China's re-vegetation program: Simulating regional impacts of afforestation on average annual streamflow in the Loess Plateau , 2007 .

[32]  Francis H. S. Chiew,et al.  PENMAN-MONTEITH, FAO-24 REFERENCE CROP EVAPOTRANSPIRATION AND CLASS-A PAN DATA IN AUSTRALIA , 1995 .

[33]  Ling Tong,et al.  Temporal and spatial variations of evapotranspiration for spring wheat in the Shiyang river basin in northwest China , 2007 .

[34]  E. Kahya,et al.  Trend analysis of streamflow in Turkey , 2004 .