LONG TERM SPATIO-TEMPORAL ANALYSIS OF ANNUAL, SEASONAL, AND EXTREME PRECIPITATION TREND OVER MENA REGION

Author(s):  
Sabah ALMAHROUQI ◽  
Mohammed SABER ◽  
Tetsuya TAKEMI ◽  
Sameh A. KANTOUSH ◽  
Tetsuya SUMI
2021 ◽  
pp. 1-20
Author(s):  
Mayara R. de Araujo ◽  
David dos S. Martins ◽  
Maurício J. Fornazier ◽  
Keiko Uramoto ◽  
Paulo S.F. Ferreira ◽  
...  

Abstract We investigated ecological patterns of richness and abundance of Anastrepha fruit flies, based on a long-term series with a dataset from 1998 to 2010, subdivided into four subseries describing pest management through the systems approach (integration of different measures, at least two of which act independently, with cumulative effects), and its impact on abundance and diversity of fruit flies. Richness and abundance were influenced by time and distance but to different extents. Spatio-temporal analysis taking into account the implementation of the systems approach revealed clear effects of the pest management on fruit fly richness and abundance. However, abundance was affected by the systems approach three years before richness was. Abundance and richness also showed different relationships with time and distance between orchards and forest. The Gompertz model, used to describe the relationship between area and species richness, was the function that showed the best fit to the data. The richness-partitioning analysis, which decomposes beta diversity, indicated different distributions of richness values and predictions for additive partitioning that were directly associated with the implementation of the systems approach. The spectral analysis projected different trends for peaks, indicating that the systems approach is able to delay the time for new population peaks of fruit flies.


2020 ◽  
Vol 10 (10) ◽  
pp. 3343
Author(s):  
Piotr Grzempowski ◽  
Janusz Badura ◽  
Wojciech Milczarek ◽  
Jan Blachowski ◽  
Tadeusz Głowacki ◽  
...  

Wrocław is a major city located in the southwestern part of Poland in an aseismic tectonic fault zone. Slow, long-term, vertical displacements have been observed there from the 1930s based on the levelling network measurements with the use of a precise levelling method. Due to the high cost of classic surveys, these were performed at intervals of several decades and the most recent measurement of ground surface displacement was performed in 1999. The main aim of this study is to determine the ground surface displacements on the area of Wrocław in the 1995–2019 period, the spatio-temporal analysis of deformations and the identification of the potential factors causing these deformations. To determine the ground movements, an advanced PSI technique and data from ERS-2, Envisat, and Sentinel-1 sensors were used. Application of SAR technology for the first time in this area, provided new knowledge about the process of deformation in short time intervals over the entire area of the city. The results verify the hypothesis on the linearity of displacements obtained from historical geodetic observations. The obtained results show that the displacements, which continue to occur in the area of Wrocław have a cyclic character with 4–5 year long period of subsidence and 2–3 year long periods of stabilization or uplift. The displacement trends indicate that the area of the city gradually subsides in relation to the reference area located on the Fore-Sudetic Block.


2021 ◽  
Author(s):  
Nikolaos Skliris ◽  
Robert Marsh ◽  
Ivan D. Haigh ◽  
Melissa Wood ◽  
Joel Hirschi ◽  
...  

Abstract Observational rain gauge/satellite and reanalysis datasets since the 1950s are evaluated for trends in mean and extreme rainfall over Mainland Southeast Asia (MSEA). Rain gauge data indicate strong increases exceeding 50% in both annual mean precipitation and various extreme precipitation indices over Vietnam and the northwestern part of the peninsula since 1979. A high degree of uncertainty is evident between reanalysis products in capturing long-term trends in continental precipitation. Evaporation increases over adjacent seas - the Arabian Sea, the Bay of Bengal, and the South China Sea in particular- may partially explain increasing precipitation in large parts of MSEA over the last 40 years. The remote influence of ENSO may also partially explain the recent precipitation trend towards a more intense regional hydrological cycle, in response to predominant La Niña states over recent decades. Increasing precipitation in MSEA is also associated with increased monsoon intensity in southeast Asia and a northward shift of the monsoon activity centre towards MSEA over 1979–2018. Long-term amplification of the regional hydrological cycle is further investigated, through analysis of CMIP5 coupled climate models in historical and RCP4.5/8.5 21st century scenario simulations. The CMIP5 ensemble mean shows robust wide-spread trends in wet season precipitation over the MSEA in both RCP scenarios linked with strong increases in evaporation in all major oceanic moisture sources. Results clearly demonstrate an intensification of the regional water cycle with increasing frequency and intensity of extreme precipitation events.


2020 ◽  
Vol 11 (S1) ◽  
pp. 68-84 ◽  
Author(s):  
Soumia Mellak ◽  
Doudja Souag-Gamane

Abstract Drought mitigation and prevention require a broader knowledge of the spatio-temporal characteristics and return periods of droughts over several years. In this research, drought characteristics (severity, duration, frequency and areal extent) have been analysed in northern Algeria by using the Standardized Precipitation Index to identify drought events from 194 precipitation stations. For frequency analysis, three Archimedean copula families were used to find a relationship between drought duration and severity. The severity–duration–frequency (SDF) and the severity–area–frequency (SAF) curves were obtained. The SDF and SAF curves are then used to build three-dimensional surfaces of drought severity, drought duration and cumulated percentage of the affected area (SDA) for each return period. It has been shown that the return periods of maximum drought events severity vary according to their durations. To address the issue of long-term droughts, a new classification of dry events based on drought severities is proposed. The obtained results show that the western part of Algeria is the most sensitive to severe/extreme droughts of short durations and high probabilities of exceedance. For long-term durations, the study area was sensitive to mild droughts with lower probabilities.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Binbin Guo ◽  
Jing Zhang ◽  
Xianyong Meng ◽  
Tingbao Xu ◽  
Yongyu Song

AbstractClimate changes significantly impact environmental and hydrological processes. Precipitation is one of the most significant climatic parameters and its variability and trends have great influences on environmental and socioeconomic development. We investigate the spatio-temporal variability of precipitation occurrence frequency, mean precipitation depth, PVI and total precipitation in China based on long-term precipitation series from 1961 to 2015. As China’s topography is diverse and precipitation is affected by topography strongly, ANUSPLIN can model the effect of topography on precipitation effectively is adopted to generate the precipitation interpolation surface. Mann–Kendall trend analysis and simple linear regression was adopted to examine long-term trend for these indicators. The results indicate ANUSPLIN precipitation surface is reliable and the precipitation variation show different regional and seasonal trend. For example, there is a sporadic with decreasing frequency precipitation trend in spring and a uniform with increasing frequency trend in summer in Yangtze Plain, which may affect spring ploughing and alteration of flood risk for this main rice-production areas of China. In north-western China, there is a uniform with increasing precipitation frequency and intensity trend, which is beneficial for this arid region. Our study could be helpful for other counties with similar climate types.


2021 ◽  
pp. 113-120
Author(s):  
M. Ruml ◽  
E. Gregorić ◽  
G. Matović ◽  
M. Vujadinović ◽  
V. Počuča ◽  
...  

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