scholarly journals Complementary relationship estimation of actual evapotranspiration in extreme cold and arid areas: a case study of the Hotan River Basin, northwest China

2017 ◽  
Vol 49 (5) ◽  
pp. 1540-1558
Author(s):  
Xiaolong Zhang ◽  
Bing Shen ◽  
Lingmei Huang ◽  
Changsen Zhao ◽  
Jiqiang Lyu ◽  
...  
Keyword(s):  
River Basin ◽  
Time Scales ◽  
Meteorological Data ◽  
Remote Sensing Data ◽  
Northwest China ◽  
Actual Evapotranspiration ◽  
Observation Data ◽  
Complementary Relationship ◽  
Mountainous Regions ◽  
Water Surplus

Abstract Application of complementary relationship (CR) approaches using only routine meteorological data is a very convenient method of estimating actual evapotranspiration (ETa). Reanalysis datasets and remote sensing data provide good tools to overcome the difficulties in obtaining observation data. This study of the Hotan River Basin (HRB) in northwest China serves as a prime example for estimation of ETa during 2006–2014 by using the modified generalized CR. Based on comparison and analysis, the maximum potential evaporation calculated by the Penman-based equation was adopted. The estimated ETa rates were verified using a regional water balance method at annual time scales because of the limited available data. The calibration parameter was calibrated based on the elevation and underlying surface types. The mean annual ETa ranged from 2.3 mm to 800 mm during 2006–2014. ETa rates in the plains regions were higher than those in the mountainous regions. Most of ETa was concentrated in the months of May to September. A water deficit occurred in the middle and lower regions, while a water surplus occurred in the upper regions. This study not only provided a new concept for calibration, but also a potential solution for different underlying surfaces and time scales.

scholarly journals Evaluation of the Performance of CFSR Reanalysis Data Set for Estimating Potential Evapotranspiration (PET) in Turkey

2021 ◽  
Author(s):  
AHMET IRVEM ◽  
Mustafa OZBULDU
Keyword(s):  
Potential Evapotranspiration ◽  
Meteorological Data ◽  
Reanalysis Data ◽  
Actual Evapotranspiration ◽  
Observation Data ◽  
Reanalysis Dataset ◽  
Data Set ◽  
Climate Forecast System Reanalysis ◽  
Mountainous Regions ◽  
Weather Stations

Abstract Evapotranspiration is an important parameter for hydrological, meteorological and agricultural studies. However, the calculation of actual evapotranspiration is very challenging and costly. Therefore, Potential Evapotranspiration (PET) is typically calculated using meteorological data to calculate actual evapotranspiration. However, it is very difficult to get complete and accurate data from meteorology stations in, rural and mountainous regions. This study examined the availability of the Climate Forecast System Reanalysis (CFSR) reanalysis data set as an alternative to meteorological observation stations in the computation of potential annual and seasonal evapotranspiration. The PET calculations using the CFSR reanalysis dataset for the period 1987-2017 were compared to data observed at 259 weather stations observed in Turkey. As a result of the assessments, it was determined that the seasons in which the CFSR reanalysis data set had the best prediction performance were the winter (C'= 0.76 and PBias = -3.77) and the autumn (C' = 0.75 and PBias = -12.10). The worst performance was observed for the summer season. The performance of the annual prediction was determined as C'= 0.60 and PBias = -15.27. These findings indicate that the results of the PET calculation using the CFSR reanalysis data set are relatively successful for the study area. However, the data should be evaluated with observation data before being used especially in the summer models.

scholarly journals Estimation of Actual Evapotranspiration by the Complementary Theory-Based Advection–Aridity Model in the Tarim River Basin, China

2018 ◽  
Vol 19 (2) ◽  
pp. 289-303 ◽  
Author(s):  
Dongnan Jian ◽  
Xiucang Li ◽  
Hemin Sun ◽  
Hui Tao ◽  
Tong Jiang ◽  
...  
Keyword(s):  
River Basin ◽  
Potential Evapotranspiration ◽  
Temporal Trends ◽  
Northwest China ◽  
Actual Evapotranspiration ◽  
Tarim River ◽  
Tarim River Basin ◽  
Complementary Relationship ◽  
The Tarim River ◽  
The Tarim River Basin

AbstractIn this study, the complementary relationship between actual evapotranspiration (ETa) and potential evapotranspiration (ETp) was verified in the Tarim River basin (TRB) in northwest China. The advection–aridity (AA) model that is based on the complementary relationship (CR) was used to calculate ETa. Spatial and temporal trends in the estimated annual ETa and the factors that influenced ETa were investigated. The multiyear average ETa in the TRB for the period from 1961 to 2014 was 178.5 mm. There was an overall significant increasing trend (at a rate of 10.6 mm decade−1) in ETa from 1961 to 2014; ETa increased at a rate of 22.9 mm decade−1 from 1961 to 1996 and decreased at a rate of 33.9 mm decade−1 from 1996 to 2014. Seasonally, ETa was strongest in summer, followed by spring and autumn. The spatial distributions of the annual and seasonal ETa were mostly consistent, with higher ETa values in the northeast, northwest, and southwest of the TRB, and lower ETa values in the mostly desert lands in the central and southeastern areas. While the energy budget (indicated by net radiation Rn) had little influence on ETa over time, the advection budget (indicated by the drying power of the air Ea) played an important role, explainable by Bouchet’s complementary relationship. In the Aksu River basin (ARB), ETa has increased because of an increase in the surface water supply (SWS). The change in ETa between 1996 and 1998 may have been caused by changes in the SWS and the advection budget during the same time period.

scholarly journals Calculation of meteorological water balance in Iraq

2020 ◽  
Vol 2 (1) ◽  
pp. 84-89
Author(s):  
Hussein Ilaibi Zamil Al-Sudani ◽  
Keyword(s):  
Water Balance ◽  
Potential Evapotranspiration ◽  
Meteorological Data ◽  
Meteorological Station ◽  
Actual Evapotranspiration ◽  
North East ◽  
Crucial Component ◽  
Water Surplus ◽  
Main Components ◽  
The Impact

The hydrology section is divided into two main components, surface and groundwater. One of the most important outcomes in the water balance equation for any natural area or water body is Evapotranspiration and it is also a crucial component of the hydrologic cycle. Prediction of monthly evapotranspiration can be obtained depending on observed monthly average temperatures at a meteorological station in each year. Calculating of water balance in Iraq depending on meteorological data and Thornthwaite method was the aim of this research. Results of corrected potential evapotranspiration (PEc) obtained from applying Thornthwaite formula were compared with annual and monthly rainfall in thirty two meteorological station in order to estimate actual evapotranspiration (AE). The results showed that the annual summation of rainfall increased from south west towards north east according to the increasing ratio of rainfall due to the impact of Mediterranean climate condition on Iraq. Actual evapotranspiration depends directly on water excess during calculating water balance. Water surplus contour map indicates increased values towards north-east direction of Iraq, where water surplus depends directly on both rainfall and actual evapotranspiration.

DETERMINATION OF VEGETATION BIOMASS PRODUCTIVITY IN THE SHARYN RIVER BASIN

2021 ◽  
Vol 101 (2) ◽  
pp. 23-32
Author(s):  
B.S. Kerimbay ◽  
◽  
M.N. Musabayeva ◽  
N.N. Kerimbay ◽  
◽  
...  
Keyword(s):  
River Basin ◽  
Meteorological Data ◽  
Remote Sensing Data ◽  
Biomass Productivity ◽  
Temporal Consistency ◽  
The Earth ◽  
Time Period ◽  
Average Annual Precipitation ◽  
Sentinel 2

The study of the biomass productivity of vegetation in the Sharyn River basin, carried out on the basis of remote sensing data, on the European digital platform for global monitoring of the Earth CGLS, the DMP module using satellite images from Sentinel-2 sensors, in combination with meteorological data from MeteoConsult (EU) for the time period 2014…2019 Spatial and temporal consistency was checked by comparing these data with climatic parameters during the vegetation part of the annual cycle. The data of Kazhydromet were studied and diagrams of the average annual precipitation and average air temperature by months for the studied period of time were built.

A Conceptual Framework for Modelling the Climate Change and its Impacts within a River Basin using Remote Sensing data

2020 ◽  
Author(s):  
Sathyaseelan Mayilvahanam ◽  
Sanjay Kumar Ghosh ◽  
Chandra Shekhar Prasad Ojha
Keyword(s):  
Climate Change ◽  
Remote Sensing ◽  
Global Warming ◽  
Conceptual Framework ◽  
River Basin ◽  
Meteorological Data ◽  
Remote Sensing Data ◽  
Spatial And Temporal Scales ◽  
Process Component ◽  
Land Hydrology

<p><strong>Abstract</strong></p> <p>In general, modelling the climate change and its impacts within a hydrological unit brings out an understanding of the system and, its behaviour with various model constrains. The climate change and global warming studies are being under research and development phase, because of its complex and dynamic nature. The IPCC 5<sup>th</sup> Assessment Report on global warming states that in the 21<sup>st</sup> century, there may be an increase in temperature of the order of ~1.5°C. This transient climate may cause significant impacts or any discrepancies in the water availability of the hydrological unit. This may lead to severe impacts in countries with high population such as India, China, etc., The Remote sensing datasets play an essential role in modelling the climatic changes for a river basin at different spatial and temporal scales. This study aims to propose a conceptual framework for the above-defined problem with emphasising on remote sensing datasets. This framework involves five entities such as the data component, process component,  impact component,  feedback component and, uncertainty component. The framework flow begins with the data component entity that involves two significant inputs, such as the hydro-meteorological data and the land-hydrology data. The essential attributes of the hydro-meteorological data entities are the precipitation, temperature, relative humidity, wind speed and solar radiation. These datasets may be obtained and analysed from empirical or statistical methods, in-situ based or satellite-based methods, respectively. These mathematical models on long-run historical climate data may provide knowledge on climate change detections or its trends. The meteorological data derived from the satellites may have a measurable bias with that of the in situ data. The satellite-based land-hydrology data component involves various attributes such as topography, soil, vegetation, water bodies, other land use / land cover, soil moisture, evapotranspiration. The process component involves complex land-hydrology processes that may be well established and modelled by customizable hydrological models. Here, we may emphasise the use of remote-sensing based model parameter values in the equations either directly or indirectly. Also, the land-atmospheric process component involves various complex processes that may take place in this zone. These processes may be well established and solved by customizable atmospheric weather models. The land components play a significant role in modelling the climate changes, because these land processes may trigger global warming by various anthropogenic agents. The main objective of this framework is to emphasise the climate change impacts using remote sensing. Hence, the impact component entity plays an essential role in this conceptual framework. The climate change impact within a river basin at various spatial and temporal scales are identified using different hydrological responses. The feedback entity is the most sensitive part of this framework, because it may alter the climate forcing either positive or negative. An uncertainty model component handles the uncertainty in the model framework. The highlight of this conceptual framework is to use the remote sensing datasets in climate change studies. The limitations on the correctness of the remote sensing data with the insitu data at every location is not feasible.</p>

scholarly journals Persistence and Corresponding Time Scales of Soil Moisture Dynamics During Summer in the Babao River Basin, Northwest China

2018 ◽  
Vol 123 (17) ◽  
pp. 8936-8948 ◽  
Author(s):  
Shi shen ◽  
Sijing Ye ◽  
Changxiu Cheng ◽  
Changqing Song ◽  
Jianbo Gao ◽  
...  
Keyword(s):  
Soil Moisture ◽  
River Basin ◽  
Time Scales ◽  
Northwest China ◽  
Soil Moisture Dynamics ◽  
Moisture Dynamics

scholarly journals Simulation of Actual Evapotranspiration and Evaluation of Three Complementary Relationships in the Upper Regions of the Mekong River and the Salween River

2021 ◽  
Author(s):  
Yongshan Jiang ◽  
Zhaofei Liu ◽  
Rui Wang ◽  
Pingcuo Gele
Keyword(s):  
Wind Speed ◽  
River Basin ◽  
Negative Correlation ◽  
Aridity Index ◽  
Actual Evapotranspiration ◽  
Upstream Region ◽  
Contribution Rate ◽  
Complementary Relationship ◽  
Annual Series ◽  
Downstream Region

Abstract Based on observed precipitation and runoff data, monthly actual evapotranspiration (ETa) was calculated by the hydrological budget balance method in the Nu River Basin (NRB) and Lancang River Basin (LCRB). The performance of three developed complementary relationship methods, the nonlinear advection-aridity (nonlinear AA) method, generalized complementary relationship method (B2015), and sigmoid generalized complementary function (H2018), on simulating (ETa) were evaluated. The evaluation results showed that three methods were able to accurately simulate monthly (ETa) series. The NSE between the monthly (ETa) simulated by the nonlinear AA, B2015, and H2018 methods and the water-balance-derived (ETa) were 0.89, 0.83, and 0.91, respectively. The R-square were 0.90, 0.84, and 0.93, respectively. Overall, the H2018 method showed the best performance. The parameter α had a negative correlation with regional aridity index. Annual (ETa) and precipitation showed significant increasing trends during 1956–2018 in the basins at all temporal scales (dry and wet seasons and annual series). Runoff also exhibited an increasing trend in each sub-basin, except for the downstream region of the LCRB. The increasing magnitudes of wet reason precipitation and runoff in the mid-stream region was the highest, with the value of 73.7 mm/10a and 44.9 mm/10a, respectively. The (ETa) increased dramatically in the downstream region, the magnitude reached 25.9 mm/10a. Precipitation was the main factor leasing to (ETa) change. The increasing magnitude of (ETa) accounted for 42.4% of the precipitation increment. Research on the influence mechanism between meteorological factors and (ETa) showed that the contribution rate of air temperature to (ETa) was the highest, reaching 23.5%, which showed a significant positive correlation. The second was wind speed, whose contribution rate was − 10.2% on average, and even reached − 14.1% in the upstream region of the NRB. The correlation coefficient between (ETa) and wind speed was highest in mid-stream region of the NRB, which was greater than 0.80. The contribution rates of increasing humidity to (ETa) were − 12.5% and − 9.2% in the NRB and LCRB, respectively. (ETa) was negatively correlated with humidity. The negative correlation was especially strong in the mid-stream region, with coefficients were greater than − 0.65. The sunshine hours had the least effect on (ETa), and the contribution rates were − 6.5% and − 4.1%, respectively.

scholarly journals Study of Persistent Pollution in Hefei during Winter Revealed by Ground-Based LiDAR and the CALIPSO Satellite

2021 ◽  
Vol 13 (2) ◽  
pp. 875
Author(s):  
Zhiyuan Fang ◽  
Hao Yang ◽  
Ye Cao ◽  
Kunming Xing ◽  
Dong Liu ◽  
...  
Keyword(s):  
Meteorological Data ◽  
Eastern China ◽  
Northwest China ◽  
Back Trajectory ◽  
Observation Data ◽  
Transport Pathway ◽  
Back Trajectory Analysis ◽  
Maximum Value ◽  
Heavy Pollution ◽  
Ground Based Lidar

LiDAR and CALIPSO satellites are effective tools for detecting air pollution, and by employing PM2.5 observation data, ground-based LiDAR measurements, CALIPSO satellite data, meteorological data, and back-trajectory analysis, we analyzed the process of pollution (moderate pollution, heavy pollution, excellent weather, and dust transmission weather) in Hefei, China from 24 to 27 January 2019 and analyzed the meteorological conditions and pollutants causing heavy pollution. Observation data from the ground station showed that the concentrations of PM10 and PM2.5 increased significantly on 25 January; the maximum value of PM10 was 175 µg/m3, and the maximum value of PM2.5 was 170 µg/m3. In this study, aerosol transboundary transport was observed using a combination of ground-based LiDAR and CALIPSO satellite observations. This method showed that aerosols were distributed at a height of 3–4 km over Hefei at 12:00 on 26 January, and it was found that the aerosols came from the desert region in northwest China. Moreover, we determined its transport pathway based on the backward trajectory, and the transportation of pollutants from the surrounding important industrial cities in central and eastern China led to severe pollution after aggregating and mixing with local aerosols in Hefei in the winter. Therefore, the method proposed in this paper can effectively monitor the optical properties and transportation process of aerosols, help to explore the causes of pollution under complex conditions, and improve environmental quality.

scholarly journals Evaluation of water productivity under climate change in irrigated areas of the arid Northwest China using an assemble statistical downscaling method and an agro-hydrological model

2018 ◽  
Vol 379 ◽  
pp. 393-402
Author(s):  
Liu Liu ◽  
Zezhong Guo ◽  
Guanhua Huang
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Statistical Downscaling ◽  
Arid Region ◽  
Meteorological Data ◽  
Water Productivity ◽  
Northwest China ◽  
Heihe River ◽  
Climate Change Scenarios ◽  
Increasing Trend

Abstract. The Heihe River Basin (HRB) is the second largest inland river basin, located in the arid region of Northwest China with a serious water shortage. Evaluation of water productivity will provide scientific implications for agricultural water-saving in irrigated areas of the arid region under climate change. Based on observed meteorological data, 23 GCMs outputs and the ERA-40 reanalysis data, an assemble statistical downscaling model was developed to generate climate change scenarios under RCP2.6, RCP4.5, RCP8.5 respectively, which were then used to drive the SWAP-EPIC model to simulate crop growth in the irrigated areas of the middle HRB for the future period from 2018 to 2047. Crop yield showed an increasing trend, while crop water consumption decreased gradually in Gaotai and Ganzhou irrigated areas. The water productivity in future 30 years showed an increasing trend in both Gaotai and Ganzhou areas, with the most significant increase under RCP4.5 scenario, which were both larger than 2 kg m−3. Compared with that of the period from 2012 to 2015, the water productivity during 2018–2047 under three RCP scenarios increased by 9.2, 14.3 and 11.8 % in the Gaotai area, and 15.4, 21.6, 19.9 % in the Ganzhou area, respectively.

scholarly journals Separating the impacts of climate change and human activities on actual evapotranspiration in Aksu River Basin ecosystems, Northwest China

2018 ◽  
Vol 49 (6) ◽  
pp. 1740-1752 ◽  
Author(s):  
Peng Yang ◽  
Jun Xia ◽  
Chesheng Zhan ◽  
Xuejuan Chen ◽  
Yunfeng Qiao ◽  
...  
Keyword(s):  
Climate Change ◽  
Wind Speed ◽  
River Basin ◽  
Human Activity ◽  
Arable Land ◽  
Northwest China ◽  
Actual Evapotranspiration ◽  
Forest Land ◽  
Aksu River Basin ◽  
Impacts Of Climate Change

Abstract Separating the impacts of climate change and human activity on actual evapotranspiration (ET) is important for reducing comprehensive risk and improving the adaptability of water resource systems. In this study, the spatiotemporal distribution of actual ET in the Aksu River Basin, Northwest China, during the period 2000–2015 was evaluated using the Vegetation Interfaces Processes model and Moderate Resolution Imaging Spectroradiometer-Normalized Difference Vegetation Index. The impact of climate change and human activity on actual ET were separated and quantified. The results demonstrated that: (1) the annual pattern of actual ET per pixel exhibited the highest values for arable land (average 362.4 mm/a/pixel), followed by forest land and grassland (average of 159.6 and 142.8 mm/a/pixel, respectively). Significant increasing linear trends (p < 0.05) of 3.2 and 1.8 mm/a were detected in the arable land and forest land time series, respectively; (2) precipitation was the most significant of the selected climate factors (precipitation, average temperature, sunshine duration, and wind speed) for all ecosystems. The second most significant was wind speed; (3) human activity caused 89%, 98%, and 80% of the changes in actual ET of forest, grass, and arable land, respectively, while climate change caused 11%, 2%, and 20% of the changes in actual ET, in the Aksu River Basin during 2000–2015.

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