scholarly journals Measurements of energy and water vapor fluxes over different surfaces in the Heihe River Basin, China

2010 ◽  
Vol 7 (6) ◽  
pp. 8741-8780 ◽  
Author(s):  
S. Liu ◽  
Z. Xu ◽  
W. Wang ◽  
J. Bai ◽  
Z. Jia ◽  
...  
Keyword(s):  
Heat Flux ◽  
Water Vapor ◽  
River Basin ◽  
Energy Budget ◽  
Seasonal Variations ◽  
Heat Fluxes ◽  
Heihe River ◽  
Sensible Heat ◽  
Source Areas ◽  
The Heihe River Basin

Abstract. We analyzed the seasonal variations of energy and water vapor fluxes over three different surfaces: irrigated cropland (Yingke, YK), alpine meadow (A'rou, AR), and spruce forest (Guantan, GT). The energy and water vapor fluxes were measured using eddy covariance systems (EC) and a large aperture scintillometer (LAS) in the Heihe River Basin, China, in 2008 and 2009. We also determined the source areas of the EC and LAS measurements with a footprint model for each site, and discussed the differences between the sensible heat fluxes measured by EC and LAS. The results show that the main EC source areas were within a radius of 250 m at all sites. The main source area for the LAS (with a path length of 2390 m) stretched along a path line approximately 2000 m long and 700 m wide. The surface characteristics in the source areas changed according to season and site, and there were characteristic seasonal variations in the energy and water vapor fluxes at all sites. The sensible heat flux was the main term of the energy budget during the dormant season. During the growing season, however, the latent heat flux dominated the energy budget, and an obvious "oasis effect" was observed at YK. The evapotranspiration (ET) at YK was larger than those at the other two sites. The monthly ET reached its peak in July at YK and in June at GT in both 2008 and 2009, while it reached its peak in August at AR in 2008 and in June in 2009. The sensible heat fluxes measured by LAS at AR were larger than those measured by EC at the same site. This difference seems to be caused by the energy imbalance of EC, the heterogeneity of the underlying surfaces, and the difference between the source areas of the LAS and EC measurements.

scholarly journals A comparison of eddy-covariance and large aperture scintillometer measurements with respect to the energy balance closure problem

2011 ◽  
Vol 15 (4) ◽  
pp. 1291-1306 ◽  
Author(s):  
S. M. Liu ◽  
Z. W. Xu ◽  
W. Z. Wang ◽  
Z. Z. Jia ◽  
M. J. Zhu ◽  
...  
Keyword(s):  
Heat Flux ◽  
Energy Balance ◽  
Eddy Covariance ◽  
Energy Budget ◽  
Seasonal Variations ◽  
Heat Fluxes ◽  
Sensible Heat ◽  
Source Areas ◽  
Large Aperture ◽  
Large Aperture Scintillometer

Abstract. We analyzed the seasonal variations of energy balance components over three different surfaces: irrigated cropland (Yingke, YK), alpine meadow (A'rou, AR), and spruce forest (Guantan, GT). The energy balance components were measured using eddy covariance (EC) systems and a large aperture scintillometer (LAS) in the Heihe River Basin, China, in 2008 and 2009. We also determined the source areas of the EC and LAS measurements with a footprint model for each site and discussed the differences between the sensible heat fluxes measured with EC and LAS at AR. The results show that the main EC source areas were within a radius of 250 m at all of the sites. The main source area for the LAS (with a path length of 2390 m) stretched along a path line approximately 2000 m long and 700 m wide. The surface characteristics in the source areas changed with the season at each site, and there were characteristic seasonal variations in the energy balance components at all of the sites. The sensible heat flux was the main term of the energy budget during the dormant season. During the growing season, however, the latent heat flux dominated the energy budget, and an obvious "oasis effect" was observed at YK. The sensible heat fluxes measured by LAS at AR were larger than those measured by EC at the same site. This difference seems to be caused by the so-called energy imbalance phenomenon, the heterogeneity of the underlying surfaces, and the difference between the source areas of the LAS and EC measurements.

scholarly journals The Impact of Mountain Range Geographic Orientation on the Altitude Effect of Precipitation δ18O in the Upper Reaches of the Heihe River Basin in the Qilian Mountains

Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1797 ◽  
Author(s):  
Jianqiao He ◽  
Wei Zhang ◽  
Yuwei Wu
Keyword(s):  
Water Vapor ◽  
River Basin ◽  
Qilian Mountains ◽  
Heihe River Basin ◽  
Heihe River ◽  
Mountain Range ◽  
The Qilian Mountains ◽  
The Impact ◽  
The Heihe River Basin ◽  
Precipitation Δ18o

The precipitation δ18O-elevation gradients are important for paleoclimate, hydrology, and paleoelevation studies. The field setting for this research was the upper reaches of the Heihe River Basin within the Qilian Mountains in the Northern Tibetan Plateau. Three study sites were established along the Heihe main river. These sites were the Yingluoxia and Qilian hydrological stations and the Yeniugou meteorological station. The Yingluoxia hydrological station was the dividing point between the upper and middle reaches of the Heihe River Basin. The altitudes of these sites range from 1600 m to 3300 m. Summer precipitation is predominant with regard to the annual precipitation amount. By analysis of variance (ANOVA), the precipitation δ18O data collected from the three sites were analyzed, spanning a year of precipitation data from 2007.10 to 2008.9. The results showed that the δ18O-elevation gradient was not significant (α = 0.05) at a seasonal or annual scale in this region and the precipitation-weighted annual mean δ18O was −7.1‰. Mechanisms that have been proposed to explain this result consider the role of two processes, including (1) mixing of moisture sources, a process common in an arid and semiarid region, and (2) the absence of a mechanism for water vapor to climb along slopes in the precipitation system. Atmospheric water vapor mainly travels along the trend of the Qilian Mountains range rather than climbing it because this region is dominated by the westerlies and the trend of the Qilian mountains is geographically aligned to the NWW (north-west-west) direction. We demonstrated that, aside from the water vapor source, the spatial relationship between the water vapor transport pathway and the trend of the mountain range are the main driving factors associated with the stable isotope trends in precipitation. As a result, it is important to re-recognize the timing and location of groundwater recharge in the Heihe River Basin.

scholarly journals Refined Characteristics of Moisture Cycling over the Inland River Basin Using the WRF Model and the Finer Box Model: A Case Study of the Heihe River Basin

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 399
Author(s):  
Xiaoduo Pan ◽  
Weiqiang Ma ◽  
Ying Zhang ◽  
Hu Li
Keyword(s):  
Water Vapor ◽  
River Basin ◽  
Wrf Model ◽  
Heihe River ◽  
The West ◽  
Moisture Recycling ◽  
Inland River ◽  
The North ◽  
Inland River Basin ◽  
The Heihe River Basin

The Heihe River Basin (HRB), located on the northeastern edge of the Tibetan Plateau, is the second-largest inland river basin in China, with an area of 140,000 km2. The HRB is a coupling area of the westerlies, the Qinghai–Tibet Plateau monsoon and the Southeast monsoon circulation system, and is a relatively independent land-surface water-circulating system. The refined characteristics of moisture recycling over the HRB was described by using the Weather Research and Forecasting (WRF) model for a long-term simulation, and the “finer box model” for calculating the net water-vapor flux. The following conclusions were drawn from the results of this study: (1) The water vapor of the HRB was dominantly transported by the wind from the west and from the north, and the west one was much larger than the north one. The net vapor transported by the west wind was positive, and by the north wind was negative. (2) The precipitation over the HRB was triggered mainly by the vapor from the west, which arose from the lower vertical layer to higher one during transporting from west to east. The vapor from the north sank from a higher layer to a lower one, and crossed the south edge of the HRB. (3) The moisture-recycling ratio of evapotranspiration to precipitation over the HRB was much higher than the other regions, which may be due to the strong land–atmosphere interaction in the arid inland river basin.

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