Spatiotemporal Evolution of the Drought and Flood in Northeast China

2014 ◽  
Vol 1010-1012 ◽  
pp. 1075-1083 ◽  
Author(s):  
Ru Huang ◽  
Deng Hua Yan
Keyword(s):  
Northeast China ◽  
Linear Regression Analysis ◽  
Kendall Test ◽  
Monthly Precipitation ◽  
Upward Trend ◽  
Spatiotemporal Evolution ◽  
Drought And Flood ◽  
Increasing Trend ◽  
Change Trend ◽  
Monthly Precipitation Data

In order to reduce the losses of drought and flood disasters, the spatiotemporal characteristics and evolution of drought and flood in Northeast China were analyzed by Z index based on the monthly precipitation data of 111 meteorological stations during 1961-2013.The Mann–Kendall test and linear regression analysis were used to analyze the change trend of drought and flood. The main conclusions are as follows: (1) Affected by the monsoon climate, flood is concentrated in summer extensively and frequently in Northeast China, while drought is concentrated in winter. (2) Drought mainly occurs in January, February, March, November and December concentrated in east and southeast of Northeast China. Flood is found in May to September. Especially The highest frequency of flood is observed in July (up to 84.9%), next is August with 69.8%, and followed by June with 48.7%. (3)7 months in a year (March-June and October-December ) show wetting trend over Northeast China , while 3 months (July-September) are observed drying trends. Significant upward trend of wet conditions occur in March and December; while significant trends towards drier conditions occur in September. (4) Drought areas dominate the Northeast China in January, February, March, November and December with a decreasing trend. Flood areas dominate the Northeast China from May to September. Extensive flood is most likely occurred in July. Flood area in May and June show an increasing trend, while a decreasing trend is from July to September.

Spatial and temporal characterization of climate at regional scale using homogeneous monthly precipitation and air temperature data: an application in Calabria (southern Italy)

2014 ◽  
Vol 46 (4) ◽  
pp. 629-646 ◽  
Author(s):  
T. Caloiero ◽  
G. Buttafuoco ◽  
R. Coscarelli ◽  
E. Ferrari
Keyword(s):  
Regional Scale ◽  
Kendall Test ◽  
Temperature Data ◽  
Winter Period ◽  
Positive Trend ◽  
Monthly Precipitation ◽  
Average Temperature ◽  
Increasing Trend ◽  
Precipitation And Temperature

In the present study, an approach for a climate characterization based on a statistical analysis of monthly precipitation and temperature data is presented. First, the original database (1916–2010) was homogenized and a geostatistical analysis was carried out to characterize the monthly mean distribution of the two variables in the study area. Then, temporal change of precipitation and temperature were evaluated through the Mann–Kendall test. Finally, to better assess the climate patterns in Calabria, a climatic characterization was carried out by means of the Péguy climograph. Results have shown a decreasing trend for autumn–winter rainfall and an increasing trend in summer. With respect to the average temperature, the analyses revealed a positive trend in late spring and summer, mainly due to the increase in the minimum values, and a negative trend in the autumn–winter period, mainly due to a decrease in the maximum values. The analysis of the Péguy climographs allowed the dataset to be divided into three groups, depending on the different elevation of the gauges. Moreover, different temporal behaviours were detected by analysing the climographs in three sub-periods.

scholarly journals Variations of precipitable water vapor from 2012 to 2019 over the Philippines using radiosondes

2021 ◽  
Vol 880 (1) ◽  
pp. 012001
Author(s):  
Y Rivera ◽  
K C Capacete ◽  
S K Rodriguez ◽  
A R David ◽  
E Macalalad
Keyword(s):  
Water Vapor ◽  
Precipitable Water ◽  
Kendall Test ◽  
The Philippines ◽  
Precipitable Water Vapor ◽  
Radiosonde Data ◽  
Upward Trend ◽  
Annual Periodicity ◽  
Increasing Trend ◽  
Moderate Positive Correlation

Abstract Precipitable Water Vapor (PWV) refers to the content of water vapor in the atmosphere which is significant in observing climate changes. The trends and variations of precipitable water vapor in Laoag, Legazpi, Mactan, and Puerto Princesa from 2012-2019, are presented through the use of radiosonde data derived from the database of the Integrated Global Radiosonde Archives (IGRA). These data were analyzed for possible patterns through a time series of its daily, monthly, and annual mean, together with a Lomb-Scargle periodogram, and Mann-Kendall test. The results observed varying trends and variability. Legazpi and Puerto Princesa with a minimum value of 20 mm, observed a gradual downward trend of PWV. Laoag and Mactan detected an upward trend of PWV with a minimum of 10 mm and 20 mm, respectively. It also showed an annual and bi-annual periodicity of PWV. Furthermore, all cities detected an increase of PWV during the wet months of May to September, while the dry months of October to April with slight variations over 8 years. In terms of seasonality, only Laoag observed a slightly different dry season, with January, February, and March experiencing around 5 mm less in monthly PWV variation compared to the other cities. The correlation of surface temperature and relative humidity of PWV observed an overall increasing trend while showing a general moderate positive correlation. This study can be used for future references for meteorologists for upcoming forecasting on the likelihood of different weather phenomena in the Philippines.

scholarly journals Historical trends and variability of temperature extremes in two climate vulnerable regions of Bangladesh

2018 ◽  
Vol 16 (2) ◽  
pp. 283-292
Author(s):  
Khalid Mahmud ◽  
Susmita Saha ◽  
Tanvir Ahmad ◽  
Ummay Saima Satu
Keyword(s):  
Kendall Test ◽  
Daily Maximum ◽  
Temperature Extremes ◽  
Upward Trend ◽  
Historical Trends ◽  
Rate Of Increase ◽  
Hot Days ◽  
Increasing Trend ◽  
Decadal Variations ◽  
Cold Extremes

Research on temperature extremes deserves more importance because it reacts sensitively to climate change. As elsewhere across the world, Bangladesh has already become a victim of temperature extremes. Hence, this study was conducted to assess the trends and variability of 11 temperature-related extreme indices based on daily maximum (TX) and daily minimum (TN) temperature recorded at Rajshahi and Barisal over the period 1976–2015. The indices were calculated on annual basis and their average annual and decadal trends were evaluated by non-parametric Mann-Kendall test and Sen’s slope estimate. Significant (p ≤ 0.01) upward trend was observed in some of the hot extremes, such as SU35: number of days with TX > 35°C and TR25: number of days with TN > 25°C, indicating that the number of days and nights with extreme hot temperature are increasing in both sites. Significant decreasing rate (-0.308 day/year) of SU25: number of days with TX > 25°C and increasing rate (1.00 day/year) of SU35 demonstrate that moderate hot days are converting to extreme hot days at Rajshahi. All cold indices showed significant (p ≤ 0.05) variations at Rajshahi implying that cold extremes are becoming severe in this area. Significant rising trend of diurnal temperature range (DTR) indicated the higher rate of increase in TX than in TN at Rajshahi. The increasing trend of all hot indices at Barisal, close to the coast, reveals more warming in hot extremes. However, no significant trends of cold indices were observed at Barisal. Significant average decadal variations of temperature indices were only observed for hot index TNx: annual maximum TN (0.372 °C/decade) and cold index CD25: number of days with TX < 25°C (4.70 days/decade) at Rajshahi and hot index SU35 (5.650 days/decade) at Barisal. So, the relatively dry western region of the country is vulnerable to both hot and cold extremes, whereas coastal area is susceptible to only hot extremes.J. Bangladesh Agril. Univ. 16(2): 283-292, August 2018

Precipitation Characteristics and Trend in the Hsiao-Ching River Basin of Jinan City during the Past 50 Years

2014 ◽  
Vol 580-583 ◽  
pp. 2029-2032
Author(s):  
Lin Lin ◽  
Jian Liu ◽  
Ji Wen Huang ◽  
Xue Qun Chen ◽  
Qing Hua Guan ◽  
...  
Keyword(s):  
Moving Average ◽  
Kendall Test ◽  
Annual Precipitation ◽  
Monthly Precipitation ◽  
Time Period ◽  
Precipitation Characteristics ◽  
Decadal Scale ◽  
Yearly Precipitation ◽  
Monthly Precipitation Data ◽  
Dominant Influence

Monthly precipitation data from Huangtai Bridge Station were used to study seasonal and annual precipitation characteristics and trend. The covered time-period is from 1956 to 2007. Different methods including linear regression, 5-year moving average, anomalies in decadal scale and the Mann-Kendall test were applied in the study. Nearly two-thirds of the total rainfall amount is concentrated in summer, with autumn and spring months to follow, and only about 3% in winter. An increasing trend in spring months is found. It starts in 1978, becomes significant after 2002, and probably continues into the future. A decreasing trend is recorded in winter and begins in 1980. No significant trend is found in summer, autumn and yearly precipitation. The same fluctuations are observed between summer and annual precipitation indicating the dominant influence of the summer season.

scholarly journals Assessing Impact of Climate Variability in Southwest Coastal Bangladesh Using Livelihood Vulnerability Index

Climate ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 107
Author(s):  
Sabrina Mehzabin ◽  
M. Shahjahan Mondal
Keyword(s):  
Climate Variability ◽  
Linear Regression Analysis ◽  
Kendall Test ◽  
Vulnerability Index ◽  
Precipitation Anomaly ◽  
Primary Data ◽  
Precipitation Concentration Index ◽  
Coastal Bangladesh ◽  
Present Decade ◽  
The Impact

This study analyzed the variability of rainfall and temperature in southwest coastal Bangladesh and assessed the impact of such variability on local livelihood in the last two decades. The variability analysis involved the use of coefficient of variation (CV), standardized precipitation anomaly (Z), and precipitation concentration index (PCI). Linear regression analysis was conducted to assess the trends, and a Mann–Kendall test was performed to detect the significance of the trends. The impact of climate variability was assessed by using a livelihood vulnerability index (LVI), which consisted of six livelihood components with several sub-components under each component. Primary data to construct the LVIs were collected through a semi-structed questionnaire survey of 132 households in a coastal polder. The survey data were triangulated and supplemented with qualitative data from focused group discussions and key informant interviews. The results showed significant rises in temperature in southwest coastal Bangladesh. Though there were no discernable trends in annual and seasonal rainfalls, the anomalies increased in the dry season. The annual PCI and Z were found to capture the climate variability better than the currently used mean monthly standard deviation. The comparison of the LVIs of the present decade with the past indicated that the livelihood vulnerability, particularly in the water component, had increased in the coastal polder due to the increases in natural hazards and climate variability. The index-based vulnerability analysis conducted in this study can be adapted for livelihood vulnerability assessment in deltaic coastal areas of Asia and Africa.

Analiza spaţio-temporară a duratei de strălucire a soarelui

2019 ◽  
Author(s):  
Rodica Cojocari ◽  
Keyword(s):  
Sunshine Duration ◽  
Meteorological Station ◽  
Upward Trend ◽  
Trend Line ◽  
Maximum Value ◽  
Increasing Trend ◽  
Spatial Aspect ◽  
Temporal Aspect ◽  
Seasonal Aspect ◽  
Annual Amount

In temporal aspect, the duration of sunshine shows a general upward trend. In seasonal aspect, spring season demonstrates an increase of about +0.2 hours, summer - about 0.1 hours, in autumn there is a trend of decreasing, according to the trend line, and the oscillation is equal to zero hours. Also we observe the increase in the number of hours in the spatial aspect. For Briceni meteorological station, the annual amount of sunshine duration varies within the limits of 1544 hours (1980) and 2326 hours (2015). The oscillation limits at the Cahul meteorological station are 1880 hours (1976) and 2604 hours (1963). At the Chisinau meteorological station, there's general increasing trend for the number of hours during which the sunshine duration is maintained, and it exhibits oscillations within 1783 hours (1989) and 2498 hours (1963). In the spatial aspect for winter, this increase +1 hour in Cahul, +0.38 hours in Briceni, and + 0.4 hours / season in Chisinau. In spring, the highest value of +2.2 hours is observed at Briceni and the lowest in Chisinau +1.9 hours / season. At Cahul meteorological station the increase was +1.4 hours. The increase in summer is +1.7 hours in Briceni and Chisinau, and only +0.9 hours in Cahul. Autumn trend line is a downward trend with a -0.3 hours decrease registered at Briceni and Chisinau meteorological stations (minimum values), and -0.6 hours in Cahul, maximum value.

scholarly journals Trends in urban storm water quality in Tallinn and influences from stormflow and baseflow

2016 ◽  
Vol 2 (1) ◽  
Author(s):  
Bharat Maharjan ◽  
Karin Pachel ◽  
Enn Loigu
Keyword(s):  
Temporal Trends ◽  
Oxygen Demand ◽  
Road Dust ◽  
Kendall Test ◽  
P Value ◽  
Upward Trend ◽  
Monotonic Trend ◽  
Acidic Rain ◽  
Interpretation Of Change

Temporal trends provide a good interpretation of change in stormwater quality over time. This study aimed to analyse trends and influences due to stormflow and baseflow. Grab samples of 18-19 years from 1995 to 2014 recorded at outlets of 7 Tallinn watersheds were analysed for monotonic trend through seasonal Mann Kendall test for long-term, short-term, baseflow and stormflow. Statistically significant downward trends (P-value (p) &lt; 0.05) were found for 6 – hydrocarbon (HC), 1 – suspended solids (SS), 3 – biological oxygen demand (BOD), 4 – total nitrogen (TN) and 2 – total phosphorus (TP) out of 7 sampling outlets over the last 10 years. Less significant decreasing trends (p > 0.05 and &lt; 0.2) for 3 – SS, 1 – BOD, 1 – TN and 1 – TP were identified. Statistically significant long-term upward trends of pH were re-vealed in 5 basins, which reduced to 2 with 5 less significant upward trends over the 10 year period, indicating improve-ments in pH reduction. Härjapea has the highest pH without trend but it includes an upward trend of TN at p = 0.051. The highly possible causes for downward trends are street sweeping, sewer network improvement, decline in sub-urban agri-cultural areas, etc. The upward trend results of pH are related to increased alkalinisation due to acidic rain, weathering of carbonate rocks, sewage discharge and alkaline road dust. In most of the basins, stormflow has more influence on trends than baseflow.

scholarly journals An Investigation into the Spatial and Temporal Variability of the Meteorological Drought in Jordan

Climate ◽  
2019 ◽  
Vol 7 (6) ◽  
pp. 82 ◽  
Author(s):  
Haitham Aladaileh ◽  
Mohammed Al Qinna ◽  
Barta Karoly ◽  
Emad Al-Karablieh ◽  
János Rakonczai
Keyword(s):  
Regression Analysis ◽  
Hierarchical Clustering ◽  
Linear Regression Analysis ◽  
Meteorological Drought ◽  
Kendall Test ◽  
Spatial And Temporal Variability ◽  
Drought Event ◽  
Mann Kendall Test ◽  
The Impact

Following the impact of droughts witnessed during the last decade there is an urgent need to develop a drought management strategy, policy framework, and action plan for Jordan. This study aims to provide a historical baseline using the standardized precipitation index (SPI) and meteorological drought maps, and to investigate the spatial and temporal trends using long-term historical precipitation records. Specifically, this study is based on the statistical analysis of 38 years of monthly rainfall data, gathered from all 29 meteorological stations that cover Jordan. The Mann–Kendall test and linear regression analysis were used to uncover evidence of long-term trends in precipitation. Drought indices were used for calculating the meteorological SPI on an annual (SPI12), 6-months (SPI6), and 3-months basis (SPI3). At each level, every drought event was characterized according to its duration, interval, and intensity. Then, drought maps were generated using interpolation kriging to investigate the spatial extent of drought events, while drought patterns were temporally characterized using multilinear regression and spatial grouped using the hierarchical clustering technique. Both annual and monthly trend analyses and the Mann–Kendall test indicated significant reduction of precipitation in time for all weather stations except for Madaba. The rate of decrease is estimated at approximately 1.8 mm/year for the whole country. The spatial SPI krig maps that were generated suggest the presence of two drought types in the spatial dimension: Local and national. Local droughts reveal no actual observed trends or repeatable patterns of occurrence. However, looking at meteorological droughts across all time scales indicated that Jordan is facing an increasing number of local droughts. With a probability of occurrence of once every two years to three years. On the other hand, extreme national droughts occur once every 15 to 20 years and last for two or more consecutive years. Linear trends indicated significant increase in drought magnitude by time with a rate of 0.02 (p < 0.0001). Regression analysis indicated that draught in Jordan is time dependent (p < 0.001) rather than being spatially dependent (p > 0.99). Hierarchical clustering was able to group national draughts into three zones, namely the northern zone, the eastern zone, and the southern zone. This study highlights the urgent need for a monitoring program to investigate local and national drought impacts on all sectors, as well as the development of a set of proactive risk management measures and preparedness plans for various physiographic regions.

scholarly journals Innovative Trend Analysis of Precipitation in the Lake Issyk-Kul Basin, Kyrgyzstan

Atmosphere ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 332 ◽  
Author(s):  
Yilinuer Alifujiang ◽  
Jilili Abuduwaili ◽  
Balati Maihemuti ◽  
Bilal Emin ◽  
Michael Groll
Keyword(s):  
Trend Analysis ◽  
Resource Planning ◽  
Kendall Test ◽  
Trend Test ◽  
Lake Basin ◽  
Positive Trend ◽  
Monthly Precipitation ◽  
Innovative Trend Analysis ◽  
Mann Kendall Test ◽  
Increasing Trends

The analysis of various characteristics and trends of precipitation is an essential task to improve the utilization of water resources. Lake Issyk-Kul basin is an upper alpine catchment, which is more susceptible to the effects of climate variability, and identifying rainfall variations has vital importance for water resource planning and management in the lake basin. The well-known approaches linear regression, Şen’s slope, Spearman’s rho, and Mann-Kendall trend tests are applied frequently to try to identify trend variations, especially in rainfall, in most literature around the world. Recently, a newly developed method of Şen-innovative trend analysis (ITA) provides some advantages of visual-graphical illustrations and the identification of trends, which is one of the main focuses in this article. This study obtained the monthly precipitation data (between 1951 and 2012) from three meteorological stations (Balykchy, Cholpon-Ata, and Kyzyl-Suu) surrounding the Lake Issyk-Kul, and investigated the trends of precipitation variability by applying the ITA method. For comparison purposes, the traditional Mann–Kendall trend test also used the same time series. The main results of this study include the following. (1) According to the Mann-Kendall trend test, the precipitation of all months at the Balykchy station showed a positive trend (except in January (Zc = −0.784) and July (Zc = 0.079)). At the Cholpon-Ata and Kyzyl-Suu stations, monthly precipitation (with the same month of multiple years averaged) indicated a decreasing trend in January, June, August, and November. At the monthly scale, significant increasing trends (Zc > Z0.10 = 1.645) were detected in February and October for three stations. (2) The ITA method indicated that the rising trends were seen in 16 out of 36 months at the three stations, while six months showed decreasing patterns for “high” monthly precipitation. According to the “low” monthly precipitations, 14 months had an increasing trend, and four months showed a decreasing trend. Through the application of the ITA method (January, March, and August at Balykchy; December at Cholpon-Ata; and July and December at Kyzyl-Suu), there were some significant increasing trends, but the Mann-Kendall test found no significant trends. The significant trend occupies 19.4% in the Mann-Kendall test and 36.1% in the ITA method, which indicates that the ITA method displays more positive significant trends than Mann–Kendall Zc. (3) Compared with the classical Mann-Kendall trend results, the ITA method has some advantages. This approach allows more detailed interpretations about trend detection, which has benefits for identifying hidden variation trends of precipitation and the graphical illustration of the trend variability of extreme events, such as “high” and “low” values of monthly precipitation. In contrast, these cannot be discovered by applying traditional methods.

scholarly journals Trends, change points and spatial variability in extreme precipitation events from 1961 to 2017 in China

2020 ◽  
Vol 51 (3) ◽  
pp. 484-504 ◽  
Author(s):  
Linchao Li ◽  
Yufeng Zou ◽  
Yi Li ◽  
Haixia Lin ◽  
De Li Liu ◽  
...  
Keyword(s):  
Extreme Precipitation ◽  
Extreme Event ◽  
Heavy Precipitation ◽  
Kendall Test ◽  
Temporal Variations ◽  
Change Points ◽  
Monthly Precipitation ◽  
Flood Peak ◽  
Extreme Precipitation Events ◽  
Precipitation Events

Abstract Extreme precipitation events vary with different sub-regions, sites and years and show complex characteristics. In this study, the temporal variations, trends with significance and change points in the annual time series of 10 extreme precipitation indices (EPIs) at 552 sites and in seven sub-regions were analyzed using the modified Mann–Kendall test and sequential Mann–Kendall analysis. Three representative (extremely wet, normal and extremely dry) years from 1961 to 2017 were selected by the largest, 50%, and smallest empirical frequency values in China. The spatiotemporal changes in the EPIs during the three representative years were analyzed in detail. The results showed that during 1961–2017, both the consecutive wet or dry days decreased significantly, while the number of heavy precipitation days had no significant trend, and the other seven wet EPIs increased insignificantly. The abrupt change years of the 10 EPIs occurred 32 and 40 times from 1963 to 1978 and from 1990 to 2016, respectively, regardless of sub-region. The extremely dry (or wet) events mainly occurred in western (or southwestern) China, implying a higher extreme event risk. The extremely wet, normal and extremely dry events from 1961 to 2017 occurred in 2016, 1997 and 2011 with empirical frequencies of 1.7%, 50% and 98.3%, respectively. In addition, 1998 was the second-most extremely wet year (empirical frequency was 3.7%). The monthly precipitation values were larger from February to August in 1998, forming a much earlier flood peak than that of 2016. The 10 EPIs had close connections with Normalized Difference Vegetation Indexes during the 12 months of 1998 and 2016. This study provides useful references for disaster prevention in China.

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