scholarly journals Entropy-Based Research on Precipitation Variability in the Source Region of China’s Yellow River

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2486
Author(s):  
Henan Gu ◽  
Zhongbo Yu ◽  
Guofang Li ◽  
Jian Luo ◽  
Qin Ju ◽  
...  
Keyword(s):  
Hydrological Cycle ◽  
Yellow River ◽  
Source Region ◽  
Monthly Precipitation ◽  
The Tibetan Plateau ◽  
Wet Season ◽  
Climatic Trend ◽  
Moisture Supply ◽  
Increasing Trend

The headwater regions in the Tibetan Plateau play an essential role in the hydrological cycle, however the variation characteristics in the long-term precipitation and throughout-the-year apportionment remain ambiguous. To investigate the spatio-temporal variability of precipitation in the source region of the Yellow River (SRYR), different time scale data during 1979–2015 were studied based on Shannon entropy theory. Long-term marginal disorder index (LMDI) was defined to evaluate the inter-annual hydrologic budget for annual (AP) and monthly precipitation (MP), and annual marginal disorder index (AMDI) to measure intra-annual moisture supply disorderliness for daily precipitation (DP). Results reveal that the AP over the SRYR exhibits remarkable variation, with an inclination rate of 2.7 mm/year, and a significant increasing trend. The climatic trend reversed from warm–dry to warm–wet around the turn of this century. The start of the wet season has advanced from May instead of June, supported by the proportion of MP in AP and the LMDI for May are both comparable with the values during June–September. May contributes the main changes in AP, as it is the only month in the wet season which shows a significant increasing trend during 1979–2015, and has a value in the LMDI that divides the basin in half spatially, the same as AP, with a high value in the northwest and low in the southeast. The AMDI roughly rises with latitude in spatial distribution, with wetlands and glaciers disturbing the continuity of the pattern for a relatively perennial moisture supply. AP has increased on northwest high-altitude areas first and then the southern corner since the beginning of this century. Wetting is mainly attributed to the enhanced southwest monsoon and the warming-induced freeze-thaw process. Meanwhile, AMDI variation concentrated on the Zoige Plateau Wetland, the headwater corner, the summit and part of the North Slope in the Bayan Har Mountain, as a result of a single or combined effect of global climate change and human protection.

scholarly journals Validation of SCIAMACHY HDO/H<sub>2</sub>O measurements using the TCCON and NDACC-MUSICA networks

2015 ◽  
Vol 8 (4) ◽  
pp. 1799-1818 ◽  
Author(s):  
R. A. Scheepmaker ◽  
C. Frankenberg ◽  
N. M. Deutscher ◽  
M. Schneider ◽  
S. Barthlott ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Hydrological Cycle ◽  
Source Region ◽  
Total Carbon ◽  
Atmospheric Composition ◽  
The Tibetan Plateau ◽  
Wet Season ◽  
Data Set ◽  
The Mean ◽  
The Impact

Abstract. Measurements of the atmospheric HDO/H2O ratio help us to better understand the hydrological cycle and improve models to correctly simulate tropospheric humidity and therefore climate change. We present an updated version of the column-averaged HDO/H2O ratio data set from the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY). The data set is extended with 2 additional years, now covering 2003–2007, and is validated against co-located ground-based total column δD measurements from Fourier transform spectrometers (FTS) of the Total Carbon Column Observing Network (TCCON) and the Network for the Detection of Atmospheric Composition Change (NDACC, produced within the framework of the MUSICA project). Even though the time overlap among the available data is not yet ideal, we determined a mean negative bias in SCIAMACHY δD of −35 ± 30‰ compared to TCCON and −69 ± 15‰ compared to MUSICA (the uncertainty indicating the station-to-station standard deviation). The bias shows a latitudinal dependency, being largest (∼ −60 to −80‰) at the highest latitudes and smallest (∼ −20 to −30‰) at the lowest latitudes. We have tested the impact of an offset correction to the SCIAMACHY HDO and H2O columns. This correction leads to a humidity- and latitude-dependent shift in δD and an improvement of the bias by 27‰, although it does not lead to an improved correlation with the FTS measurements nor to a strong reduction of the latitudinal dependency of the bias. The correction might be an improvement for dry, high-altitude areas, such as the Tibetan Plateau and the Andes region. For these areas, however, validation is currently impossible due to a lack of ground stations. The mean standard deviation of single-sounding SCIAMACHY–FTS differences is ∼ 115‰, which is reduced by a factor ∼ 2 when we consider monthly means. When we relax the strict matching of individual measurements and focus on the mean seasonalities using all available FTS data, we find that the correlation coefficients between SCIAMACHY and the FTS networks improve from 0.2 to 0.7–0.8. Certain ground stations show a clear asymmetry in δD during the transition from the dry to the wet season and back, which is also detected by SCIAMACHY. This asymmetry points to a transition in the source region temperature or location of the water vapour and shows the added information that HDO/H2O measurements provide when used in combination with variations in humidity.

scholarly journals Validation of SCIAMACHY HDO/H<sub>2</sub>O measurements using the TCCON and NDACC-MUSICA networks

2014 ◽  
Vol 7 (11) ◽  
pp. 11799-11851 ◽  
Author(s):  
R. A. Scheepmaker ◽  
C. Frankenberg ◽  
N. M. Deutscher ◽  
M. Schneider ◽  
S. Barthlott ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Hydrological Cycle ◽  
Source Region ◽  
Correlation Coefficients ◽  
Total Carbon ◽  
Atmospheric Composition ◽  
The Tibetan Plateau ◽  
Wet Season ◽  
The Mean ◽  
The Impact

Abstract. Measurements of the atmospheric HDO/H2O ratio help us to better understand the hydrological cycle and improve models to correctly simulate tropospheric humidity and therefore climate change. We present an updated version of the column-averaged HDO/H2O ratio dataset from the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY). The dataset is extended with two additional years, now covering 2003–2007, and is validated against co-located ground-based total column δD measurements from Fourier-Transform Spectrometers (FTS) of the Total Carbon Column Observing Network (TCCON) and the Network for the Detection of Atmospheric Composition Change (NDACC, produced within the framework of the MUSICA project). Even though the time overlap between the available data is not yet ideal, we determined a mean negative bias in SCIAMACHY δD of −35±30‰ compared to TCCON and −69±15‰ compared to MUSICA (the uncertainty indicating the station-to-station standard deviation). The bias shows a latitudinal dependency, being largest (∼ −60 to −80‰) at the highest latitudes and smallest (∼ −20 to −30‰) at the lowest latitudes. We have tested the impact of an offset correction to the SCIAMACHY HDO and H2O columns. This correction leads to a humidity and latitude dependent shift in δD and an improvement of the bias by 27‰, although it does not lead to an improved correlation with the FTS measurements nor to a strong reduction of the latitudinal dependency of the bias. The correction might be an improvement for dry, high-altitude areas, such as the Tibetan Plateau and the Andes region. For these areas, however, validation is currently impossible due to a lack of ground stations. The mean standard deviation of single-sounding SCIAMACHY–FTS differences is ∼ 115‰, which is reduced by a factor ∼ 2 when we consider monthly means. When we relax the strict matching of individual measurements and focus on the mean seasonalities using all available FTS data, we find that the correlation coefficients between SCIAMACHY and the FTS networks improve from 0.2 to 0.7–0.8. Certain ground stations show a clear asymmetry in δD during the transition from the dry to the wet season and back, which is also detected by SCIAMACHY. This asymmetry points to a transition in the source region temperature or location of the water vapor, and shows the added information that HDO/H2O measurements provide, if used in combination with variations in humidity.

scholarly journals Recent Changes in the Moisture Source of Precipitation over the Tibetan Plateau

2017 ◽  
Vol 30 (5) ◽  
pp. 1807-1819 ◽  
Author(s):  
Chi Zhang ◽  
Qiuhong Tang ◽  
Deliang Chen
Keyword(s):  
Tibetan Plateau ◽  
Land Surface ◽  
Hydrological Cycle ◽  
Land Surface Model ◽  
Water Vapor Transport ◽  
Surface Model ◽  
The Tibetan Plateau ◽  
Precipitation Trend ◽  
Moisture Source ◽  
Moisture Supply

Abstract Evidence has suggested a wetting trend over part of the Tibetan Plateau (TP) in recent decades, although there are large uncertainties in this trend due to sparse observations. Examining the change in the moisture source for precipitation over a region in the TP with the most obvious increasing precipitation trend may help understand the precipitation change. This study applied the modified Water Accounting Model with two atmospheric reanalyses, ground-observed precipitation, and evaporation from a land surface model to investigate the change in moisture source of the precipitation over the targeted region. The study estimated that on average more than 69% and more than 21% of the moisture supply to precipitation over the targeted region came from land and ocean, respectively. The moisture transports from the west of the TP by the westerlies and from the southwest by the Indian summer monsoon likely contributed the most to precipitation over the targeted region. The moisture from inside the region may have contributed about 18% of the total precipitation. Most of the increased moisture supply to the precipitation during 1979–2013 was attributed to the enhanced influx from the southwest and the local moisture supply. The precipitation recycling ratio over the targeted region increased significantly, suggesting an intensified hydrological cycle. Further analysis at monthly scale and with wet–dry-year composites indicates that the increased moisture contribution was mainly from the southwest and the targeted region during May and September. The enhanced water vapor transport from the Indian Ocean during July and September and the intensified local hydrological recycling seem to be the primary reasons behind the recent precipitation increase over the targeted region.

scholarly journals Long-term Spatiotemporal Trend Analysis of Precipitation and Temperature in Citarum Watershed, Indonesia

2021 ◽  
Vol 930 (1) ◽  
pp. 012038
Author(s):  
R Rahmad ◽  
M A Wirda
Keyword(s):  
Warming Trend ◽  
Tropical Region ◽  
Wet Season ◽  
Increasing Trend ◽  
Considerable Impact ◽  
Urbanization Rate ◽  
Increasing Trends ◽  
The City ◽  
Precipitation And Temperature

Abstract Analyzing meteorological variables such as precipitation and temperature can give valuable information regarding past and future climate variability. Citarum Watershed is one of the world’s most threatened watersheds and the most degraded on Indonesia’s Java Island. The Indonesian government regards it as the most strategically important river basin territory because it supplies 80 percent of the surface water supply to Jakarta. This study aims to analyze the precipitation and temperature trend in the Citarum Watershed. This study is preliminary research and intends to provide a better insight into the impacts of climate change on water availability in the tropical region. The detection was carried out with the use of a Mann-Kendall with Sen’s slope. The results indicated that there are significant increasing trends of precipitation during the wet season. Whereas the increasing trend in temperature exhibits for all stations in the basin. The highest increasing trend is in Bandung City, the city with the highest urbanization rate in Indonesia. It is widely acknowledged that rising urbanization will have a considerable impact on the worldwide land warming trend.

scholarly journals Evaluating the Spatiotemporal Characteristics of Meteorological Drought in Bangladesh Using Effective Drought Index

2019 ◽  
Author(s):  
Mohammad Kamruzzaman ◽  
Syewoon Hwang ◽  
Jaepil Cho ◽  
Min-Won Jang ◽  
Hanseok Jeong
Keyword(s):  
Central Region ◽  
Drought Index ◽  
Regional Scale ◽  
Mitigation Strategies ◽  
Monthly Precipitation ◽  
Effective Drought Index ◽  
Spatiotemporal Characteristics ◽  
Increasing Trend ◽  
North Western

This study aims to assess the spatiotemporal characteristics of meteorological droughts in Bangladesh during 1981&ndash;2015 using the Effective Drought Index (EDI). Monthly precipitation data for 36 years (1980-2015) obtained from 27 metrological stations, were used in this study. The EDI performance was evaluated for four sub-regions over the country through comparisons with historical drought records identified at the regional scale. Analysis at a regional level showed that EDI could reasonably detect the drought years/events during the study period. The study also revealed that the overall drought severity had increased during the past 35 y; the most significant increasing trend was observed in the central region. The characteristics (severity and duration) of drought were also analysed in terms of spatiotemporal evolution of the frequency of drought events. It was found that the western and central regions of the country are comparatively more vulnerable to drought. Moreover, the southwestern region is more prone to extreme drought, whereas the central region is more prone to severe droughts. In addition, the central region was more prone to extra-long-term droughts, while the coastal areas in the southwestern as well as in the central and north-western region were more prone to long-term droughts. The frequency of droughts in all categories significantly increased during the last quinquennial period (2011 to 2015). The seasonal analysis showed that the north-western areas were prone to extreme droughts during the Kharif (wet) and Rabi (dry) seasons. The central and northern regions were affected by recurring severe droughts in all cropping seasons. Further, the most significant increasing trend of the drought-affected area was observed within the central region, especially during the pre-monsoon (March-May) season. The results of this study can aid policymakers in the development of drought mitigation strategies in the future.

scholarly journals Seasonal Variations in Dissolved Organic Carbon in the Source Region of the Yellow River on the Tibetan Plateau

Water ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 2901
Author(s):  
Xiaoni You ◽  
Xiangying Li
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Yellow River ◽  
Source Region ◽  
Precipitation Amount ◽  
Transport Processes ◽  
The Yellow River ◽  
Deposition Flux ◽  
The Tibetan Plateau ◽  
Permafrost Degradation

Rivers as the link between terrestrial ecosystems and oceans have been demonstrated to transport a large amount of dissolved organic carbon (DOC) to downstream ecosystems. In the source region of the Yellow River (SRYR), climate warming has resulted in the rapid retreat of glaciers and permafrost, which has raised discussion on whether DOC production will increase significantly. Here, we present three-year data of DOC concentrations in river water and precipitation, explore the deposition and transport processes of DOC from SRYR. Results show that annual mean concentrations of riverine DOC ranged from 2.03 to 2.34 mg/L, with an average of 2.21 mg/L. Its seasonal variation is characterized by the highest concentration in spring and summer (2.65 mg/L and 2.62 mg/L, respectively), followed by autumn (1.95 mg/L), and the lowest in winter (1.44 mg/L), which is closely related to changes in river runoff under the influence of precipitation and temperature. The average concentration of DOC in precipitation (2.18 mg/L) is comparable with riverine DOC, while the value is inversely related to precipitation amount and is considered to be the result of precipitation dilution. DOC deposition flux in precipitation that is affected by both precipitation amount and DOC concentration roughly was 86,080, 105,804, and 73,072 tons/yr from 2013 to 2015, respectively. DOC flux delivered by the river ranged from 24,629 to 37,539 tons/yr and was dominated by river discharge. Although permafrost degradation in SRYR is increasing, DOC yield is not as significant as previously assumed and is much less than other large rivers in the world.

scholarly journals Effects of Human Activities on Hydrological Components in the Yiluo River Basin in Middle Yellow River

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 689 ◽  
Author(s):  
Xiujie Wang ◽  
Pengfei Zhang ◽  
Lüliu Liu ◽  
Dandan Li ◽  
Yanpeng Wang
Keyword(s):  
Land Use ◽  
River Basin ◽  
Assessment Tool ◽  
Hydrological Cycle ◽  
Yellow River ◽  
Delta Method ◽  
Mitigation Measures ◽  
Wet Season ◽  
Groundwater Exploitation ◽  
Hydrological Balance

Land use and land cover change (LUCC) and water resource utilization behavior and policy (WRUBAP) affect the hydrological cycle in different ways. Their effects on streamflow and hydrological balance components were analyzed in the Yiluo River Basin using the delta method and the Soil and Water Assessment Tool (SWAT). The multivariable (runoff and actual evapotranspiration) calibration and validation method was used to reduce model uncertainty. LUCC impact on hydrological balance components (1976–2015) was evaluated through comparison of simulated paired land use scenarios. WRUBAP impact on runoff was assessed by comparing natural (simulated) and observed runoff. It showed that urban area reduction led to decreased groundwater, but increased surface runoff and increased water area led to increased evaporation. LUCC impact on annual runoff was found limited; for instance, the difference under the paired scenarios was <1 mm. Observed runoff was 34.7–144.1% greater than natural runoff during November–June because of WRUBAP. The effect of WRUBAP on wet season runoff regulation was limited before the completion of the Guxian Reservoir, whereas WRUBAP caused a reduction in natural runoff of 21.6–35.0% during the wet season (July–October) after its completion. The results suggest that WRUBAP has greater influence than LUCC on runoff in the Yiluo River Basin. Based on existing drought mitigation measures, interbasin water transfer measures and deep groundwater exploitation could reduce the potential for drought attributable to predicted future climate extremes. In addition to reservoir regulation, conversion of farmland to forestry in the upstream watershed could also reduce flood risk.

Hydro Climatic Trend and Periodicity for the Source Region of the Yellow River

2015 ◽  
Vol 20 (10) ◽  
pp. 05015003 ◽  
Author(s):  
Feifei Yuan ◽  
Ronny Berndtsson ◽  
Linus Zhang ◽  
Cintia Bertacchi Uvo ◽  
Zhenchun Hao ◽  
...  
Keyword(s):  
Yellow River ◽  
Source Region ◽  
The Yellow River ◽  
Climatic Trend

scholarly journals Impacts of the Two Biggest Lakes on Local Temperature and Precipitation in the Yellow River Source Region of the Tibetan Plateau

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Lijuan Wen ◽  
Shihua Lv ◽  
Zhaoguo Li ◽  
Lin Zhao ◽  
Nidhi Nagabhatla
Keyword(s):  
Tibetan Plateau ◽  
Yellow River ◽  
Source Region ◽  
Maximum Temperature ◽  
The Yellow River ◽  
The Tibetan Plateau ◽  
Lake Area ◽  
Local Climate ◽  
Community Land Model ◽  
Yellow River Source

The Tibetan Plateau harbors thousands of lakes; however few studies focus on impacts of lakes on local climate in the region. To investigate and quantify impacts of the two biggest lakes (Ngoring Lake and Gyaring Lake) of the Yellow River source region in the Tibetan Plateau on local climate, two simulations (with and without the two large lakes) from May 2010 to July 2011 are performed and analyzed using the WRF-CLM model (the weather research and forecasting model coupled with the community land model). Differences between simulated results show that the WRF-CLM model could provide realistic reproduction of surface observations and has better simulation after considering lakes. Lakes mostly reduce the maximum temperature all year round and increase the minimum temperature except in March due to the large heat capacity that makes lakes absorb (release) more energy for the same temperature change compared to land. Lakes increase precipitation over the lake area and in the nearby region, mostly during 02–14 BT (Beijing Time) of July to October when the warm lake surface induces the low level horizontal convergence and updraft over lake and provides energy and vapor to benefit the development of the convection for precipitation.

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