scholarly journals SPEI-Based Spatiotemporal Analysis of Drought in Haihe River Basin from 1961 to 2010

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Meijian Yang ◽  
Denghua Yan ◽  
Yingdong Yu ◽  
Zhiyong Yang
Keyword(s):  
River Basin ◽  
Temporal Variability ◽  
Break Point ◽  
Spatiotemporal Analysis ◽  
Haihe River Basin ◽  
Severe Drought ◽  
Haihe River ◽  
The North ◽  
Moderate Drought ◽  
Drought Occurrence

Under the background of climate change, the monthly accumulated precipitation and monthly averaged temperature of 47 meteorological stations in and around Haihe River Basin (HRB) were analyzed using Standardized Precipitation Evapotranspiration Indices (SPEI) to obtain the temporal variability and spatial distribution of different drought levels during the last 50 years with the support of GIS. The results show that(1)from 1961 to 2010 the drought frequency and degree in annual and seasonal scale are rising and the affecting areas of all degrees of drought have a temporal variability of increasing trend. The ratios that the influencing area of drought, light drought, moderate drought, severe drought, and extreme drought account for the whole HRB area are increasing with gradients of 0.64%/a, 0.18%/a, 0.31%/a, 0.14%/a, and 0.01%/a, respectively, and(2)there is a climate break point which occurred in 1990; after the comparison of the drought happening probability between 1961 and 1990 and between 1991 and 2010, all degrees of drought occurrence probability have a remarkable rising trend, and the drought concentrating regions moved from the north HRB to the central HRB.

scholarly journals Causal effects of dams and land cover changes on flood changes in mainland China

2020 ◽  
Author(s):  
Wencong Yang ◽  
Hanbo Yang ◽  
Dawen Yang ◽  
Aizhong Hou
Keyword(s):  
Human Factors ◽  
River Basin ◽  
Urban Areas ◽  
Yellow River ◽  
Mainland China ◽  
Yellow River Basin ◽  
Small Samples ◽  
Haihe River Basin ◽  
Haihe River ◽  
The North

Abstract. Quantifying the effects of human activities on floods is challenging because the knowledge and observations toward the effects are limited. Many previous methods fail to isolate different effects and reduce the uncertainty caused by small samples. We use panel regressions to derive the sensitivity of annual maximum discharges (Q) to the changing values of three human factors: urban areas, cropland areas, and reservoir indexes for large and middle dams. We also test whether the effects increase or decrease with increasing initial values of human factors. This method is applied in 2739 hydrological stations in China. Results show that a 1 % increase of urban areas causes around a 2.9 % increase of Q. Cropland areas have no significant effect on Q. Reservoir index has a decreasing effect: a 1 unit increase of reservoir index causes a decrease in Q from 23.1 % to 5.4 % for catchments with initial reservoir indexes from 0 to 5. From 1992 to 2017, increasing urban areas cause more than 10 % increases in Q in 10.4 % of the 2739 catchments, most of which are located in the North Plain of China. From 1960 to 2017, increasing reservoir indexes cause a more than 10 % decrease of Q in 53.4 % of 777 catchments with at least one dam. Among 1074 catchments with limited impacts from urban areas and reservoir indexes, 210 (19.6 %) catchments have more than 10 % unexplained decreasing rates in Q per decade during 1960–2017, and 62.4 % of the 210 catchments are located in the middle and down streams of the Yellow River Basin and the upper streams of the Haihe River Basin. This study extends the panel regression method in hydrology and sheds light on the attribution of flood changes on a national scale.

Multi-models for SPI drought forecasting in the north of Haihe River Basin, China

2017 ◽  
Vol 31 (10) ◽  
pp. 2471-2481 ◽  
Author(s):  
Yuhu Zhang ◽  
Weiwei Li ◽  
Qiuhua Chen ◽  
Xiao Pu ◽  
Liu Xiang
Keyword(s):  
River Basin ◽  
Haihe River Basin ◽  
Drought Forecasting ◽  
Haihe River ◽  
The North

scholarly journals Characterization of Historical Trends of Droughts and Pluvial Scenarios over Kenya, East Africa

2019 ◽  
Author(s):  
Brian AYUGI ◽  
Guirong Tan ◽  
Niu Rouyun ◽  
Dong Zeyao ◽  
Moses Ojara ◽  
...  
Keyword(s):  
Extreme Events ◽  
Spatiotemporal Analysis ◽  
Severe Drought ◽  
Drought Event ◽  
Historical Trends ◽  
Extreme Flood ◽  
Moderate Drought ◽  
Year 2000 ◽  
Drought Occurrence

This work examines drought and pluvial events based on Standardized Precipitation-Evapotranspiration Index (SPEI) over Kenya from 1981 to 2016. Spatiotemporal analysis of dry and wet events is conducted for 3 and 12-month SPEI. The drought incidences were observed during the period 1984, 1987, 2000, 2006, 2009, 2015, and 2016 for SPEI-3 whilst the SPEI-12 demonstrated the manifestation of drought during the year 2000 and 2006. SPEI clearly shows the wettest period, 1997 and 1998 coinciding with the El Nino event in both time steps. SPEI -3 shows a reduction in moderate drought events while severe and extreme cases were on increase towards the end of the twentieth century. Conversely, SPEI-12 depicts an overall severe drought occurrence over the study location with observed intensity of -1.54 and cumulative frequency of 64 months during the study period. The trend of wet events is upwards in the western and central highlands while the rest of the regions show increase in dry events during the study period. Moreover, moderate dry/wet events predominate whilst extreme events occur least frequent across all grid cells. It is apparent that the study area experiences mild extreme dry events in both categories although moderately severe dry events dominate most parts of the study area. High intensity and frequency of drought is noted in SPEI-3 while least occurrences of extreme events are recorded in SPEI-12. Although drought event prevails across the study area, there is evidence of extreme flood conditions over the recent decades.

Long-term variation of water vapor content and precipitation in the Haihe river basin

2014 ◽  
Vol 6 (2) ◽  
pp. 341-351 ◽  
Author(s):  
Chun Chang ◽  
Ping Feng ◽  
Fawen Li ◽  
Yunming Gao
Keyword(s):  
Water Vapor ◽  
River Basin ◽  
Reanalysis Data ◽  
Water Vapor Content ◽  
Haihe River Basin ◽  
Haihe River ◽  
Annual Water ◽  
Environmental Prediction ◽  
High Consistency ◽  
The Haihe River Basin

Based on the Haihe river basin National Centers for Environmental Prediction/National Center for Atmospheric Research reanalysis data from 1948 to 2010 and the precipitation data of 53 hydrological stations during 1957–2010, this study analyzed the variation of water vapor content and precipitation, and investigated the correlation between them using several statistical methods. The results showed that the annual water vapor content decreased drastically from 1948 to 2010. It was comparatively high from the late 1940s to the late 1960s and depreciated from the early 1970s. From the southeast to the northwest of the Haihe river basin, there was a decrease in water vapor content. For vertical distribution, water vapor content from the ground to 700 hPa pressure level accounted for 72.9% of the whole atmospheric layer, which indicated that the water vapor of the Haihe river basin was mainly in the air close to the ground. The precipitation in the Haihe river basin during 1957–2010 decreased very slightly. According to the correlation analysis, the precipitation and water vapor content changes showed statistically positive correlation, in addition, their break points were both in the 1970s. Furthermore, the high consistency between the precipitation efficiency and precipitation demonstrates that water vapor content is one of the important factors in the formation of precipitation.

scholarly journals Spatial and Temporal Variation Characteristics of Snowfall in the Haihe River Basin from 1960 to 2016

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1798
Author(s):  
Xu Wu ◽  
Su Li ◽  
Bin Liu ◽  
Dan Xu
Keyword(s):  
Temporal Variation ◽  
River Basin ◽  
Spatial And Temporal Variation ◽  
Haihe River Basin ◽  
Temperature Threshold ◽  
Threshold Method ◽  
Exponential Equation ◽  
Haihe River ◽  
The Haihe River Basin ◽  
Different Levels

The spatio-temporal variation of precipitation under global warming had been a research hotspot. Snowfall is an important part of precipitation, and its variabilities and trends in different regions have received great attention. In this paper, the Haihe River Basin is used as a case, and we employ the K-means clustering method to divide the basin into four sub-regions. The double temperature threshold method in the form of the exponential equation is used in this study to identify precipitation phase states, based on daily temperature, snowfall, and precipitation data from 43 meteorological stations in and around the Haihe River Basin from 1960 to 1979. Then, daily snowfall data from 1960 to 2016 are established, and the spatial and temporal variation of snowfall in the Haihe River Basin are analyzed according to the snowfall levels as determined by the national meteorological department. The results evalueted in four different zones show that (1) the snowfall at each meteorological station can be effectively estimated at an annual scale through the exponential equation, for which the correlation coefficient of each division is above 0.95, and the relative error is within 5%. (2) Except for the average snowfall and light snowfall, the snowfall and snowfall days of moderate snow, heavy snow, and snowstorm in each division are in the order of Zones III > IV > I > II. (3) The snowfall and the number of snowfall days at different levels both show a decreasing trend, except for the increasing trend of snowfall in Zone I. (4) The interannual variation trend in the snowfall at the different levels are not obvious, except for Zone III, which shows a significant decreasing trend.

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