scholarly journals Seasonal and Annual Trends of Rainfall and Streamflow in the Mae Klong Basin, Thailand

2018 ◽  
pp. 77-90
Author(s):  
Alamgir Khalil ◽  
Areeya Rittima ◽  
Yutthana Phankamolsil
Keyword(s):  
Water Resources ◽  
Kendall Test ◽  
Dry Season ◽  
Wet Season ◽  
Lower Region ◽  
Trend Slope ◽  
Rainfall Trends ◽  
Annual Trends ◽  
Annual Scale ◽  
Increasing Trends

This study examined seasonal and annual trends of rainfall and streamflow data in the Mae Klong Basin, Thailand. Monthly data of eight key rainfall stations and ten streamflow stations were analyzed to detect trends using the non-parametric Mann-Kendall test, whilst the magni-tude of the trends was determined by Sen’s slope method for the period 2000-2015. For 75% ofthe analyzed stations,rainfall was found to increase in the wet season and decrease in the dry season. Station 130013 situated in the lower region showed a statistically significant increasing trend with a trend slope of 16.02 mma-1in the wet season, while station 130042-also located in the lower region of the basin-showed a statistically significant decreasing trend, with a trend slope of23.60 mma-1in the dry season. On an annual basis, 63%of the analyzed stations showed increasing rainfall trends, particularly in the central and lower regions of the Mae Klong Basin; however, rainfall trends in the upper region were found to be decreasing, which reflected water contributions to two main reservoirs in the upper part. The trends of naturalized inflow of Srinagarind and Vajiralongkorn Reservoirs were found to be decreasing on both seasonal and annual bases, while two naturalized streamflow stations located in Lam Taphoen and Lampachi sub-basins in the central and lower regions, respectively, showed increasing trends in both dry and wet seasons. The trends of regulated streamflow stations downstream of 4 main dams which were a result of reservoir operation were found to mostly decrease on an annual scale. Results of this study can help water resources managers enhance accuracy of assessment and effective planning of water resources management in the basin.

scholarly journals Analysis of rainfall trends over Tripura

MAUSAM ◽  
2022 ◽  
Vol 73 (1) ◽  
pp. 27-36
Author(s):  
RANJAN PHUKAN ◽  
D. SAHA
Keyword(s):  
Heavy Rainfall ◽  
Monsoon Season ◽  
Rainfall Variability ◽  
Kendall Test ◽  
Annual Rainfall ◽  
The North ◽  
Rainfall Trends ◽  
Annual Scale ◽  
Increasing Trends ◽  
Rainy Days

Rainfall in India has very high temporal and spatial variability. The rainfall variability affects the livelihood and food habits of people from different regions. In this study, the rainfall trends in two stations in the north-eastern state of Tripura, namely Agartala and Kailashahar have been studied for the period 1955-2017. The state experiences an annual mean of more than 2000 mm of rainfall, out of which, about 60% occurs during the monsoon season and about 30% in pre-monsoon. An attempt has been made to analyze the trends in seasonal and annual rainfall, rainy days and heavy rainfall in the two stations, during the same period.Non-parametric Mann-Kendall test has been used to find out the significance of these trends. Both increasing and decreasing trends are observed over the two stations. Increasing trends in rainfall, rainy days and heavy rainfall are found at Agartala during pre-monsoon season and decreasing trends in all other seasons and at annual scale. At Kailashahar, rainfall amount (rainy days & heavy rainfall) is found to be increasing during pre-monsoon and monsoon seasons (pre-monsoon season). At annual scale also, rainfall and rainy days show increasing trends at Kailashahar. The parameters are showing decreasing trends during all other seasons at the station. Rainy days over Agartala show a significantly decreasing trend in monsoon, whereas no other trend is found to be significant over both the stations.  

scholarly journals Contribution of glacier runoff to water resources of La Paz city, Bolivia (16° S)

2015 ◽  
Vol 56 (70) ◽  
pp. 147-154 ◽  
Author(s):  
Alvaro Soruco ◽  
Christian Vincent ◽  
Antoine Rabatel ◽  
Bernard Francou ◽  
Emmanuel Thibert ◽  
...  
Keyword(s):  
Water Resources ◽  
Mass Balance ◽  
Dry Season ◽  
Complete Disappearance ◽  
Wet Season ◽  
Drainage Basins ◽  
La Paz ◽  
Ice Melt ◽  
Surface Areas ◽  
Annual Scale

AbstractThe supply of glacier water to La Paz city, Bolivia, between 1963 and 2006 was assessed at annual and seasonal timescales based on the mass-balance quantification of 70 glaciers located within the drainage basins of La Paz. Glaciers contributed ∼15% of water resources at an annual scale (14% in the wet season, 27% in the dry season). Uncertainties in our estimation are related to the assumed constant precipitation (∼0.5% for ice-free areas and up to 6.5% for glaciated areas), the constant runoff coefficient (∼1%), the surface areas of the glaciers and catchments (∼5%) and the mean mass-balance uncertainty of the 21 glaciers used to obtain the mass balance of the 70 glaciers (12% of the total discharge). Despite the loss of 50% of the glacierized area during the study period, runoff at La Paz did not change significantly, showing that increase in ice melt rates compensated for reduction in the surface area of the glaciers. In the future, assuming complete disappearance of the glaciers and no change in precipitation, runoff should diminish by ∼12% at an annual scale, 9% during the wet season and 24% during the dry season.

scholarly journals Quantification of Temporal Variations in Base Flow Index Using Sporadic River Data: Application to the Bua Catchment, Malawi

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 901 ◽  
Author(s):  
Laura Kelly ◽  
Robert M. Kalin ◽  
Douglas Bertram ◽  
Modesta Kanjaye ◽  
Macpherson Nkhata ◽  
...  
Keyword(s):  
Water Resources ◽  
River Flow ◽  
Temporal Variations ◽  
Dry Season ◽  
Base Flow ◽  
Flow Index ◽  
Wet Season ◽  
Data Application ◽  
Base Flow Index ◽  
Long Term Trends

This study investigated how sporadic river datasets could be used to quantify temporal variations in the base flow index (BFI). The BFI represents the baseflow component of river flow which is often used as a proxy indicator for groundwater discharge to a river. The Bua catchment in Malawi was used as a case study, whereby the smoothed minima method was applied to river flow data from six gauges (ranging from 1953 to 2009) and the Mann-Kendall (MK) statistical test was used to identify trends in BFI. The results showed that baseflow plays an important role within the catchment. Average annual BFIs > 0.74 were found for gauges in the lower reaches of the catchment, in contrast to lower BFIs < 0.54 which were found for gauges in the higher reaches. Minimal difference between annual and wet season BFI was observed, however dry season BFI was >0.94 across all gauges indicating the importance of baseflow in maintaining any dry season flows. Long term trends were identified in the annual and wet season BFI, but no evidence of a trend was found in the dry season BFI. Sustainable management of the investigated catchment should, therefore, account for the temporal variations in baseflow, with special regard to water resources allocation within the region and consideration in future scheme appraisals aimed at developing water resources. Further, this demonstration of how to work with sporadic river data to investigate baseflow serves as an important example for other catchments faced with similar challenges.

scholarly journals Seasonality and pathogen transmission in pastoral cattle contact networks

2017 ◽  
Vol 4 (12) ◽  
pp. 170808 ◽  
Author(s):  
Kimberly VanderWaal ◽  
Marie Gilbertson ◽  
Sharon Okanga ◽  
Brian F. Allan ◽  
Meggan E. Craft
Keyword(s):  
Water Resources ◽  
Disease Outbreaks ◽  
Dry Season ◽  
Pathogen Transmission ◽  
Contact Network ◽  
Wet Season ◽  
Contact Networks ◽  
Contact Rates ◽  
Animal Populations ◽  
The Impact

Capturing heterogeneity in contact patterns in animal populations is essential for understanding the spread of infectious diseases. In contrast to other regions of the world in which livestock movement networks are integral to pathogen prevention and control policies, contact networks are understudied in pastoral regions of Africa due to the challenge of measuring contact among mobile herds of cattle whose movements are driven by access to resources. Furthermore, the extent to which seasonal changes in the distribution of water and resources impacts the structure of contact networks in cattle is uncertain. Contact networks may be more conducive to pathogen spread in the dry season due to congregation at limited water sources. Alternatively, less abundant forage may result in decreased pathogen transmission due to competitive avoidance among herds, as measured by reduced contact rates. Here, we use GPS technology to concurrently track 49 free-roaming cattle herds within a semi-arid region of Kenya, and use these data to characterize seasonal contact networks and model the spread of a highly infectious pathogen. This work provides the first empirical data on the local contact network structure of mobile herds based on quantifiable contact events. The contact network demonstrated high levels of interconnectivity. An increase in contacts near to water resources in the dry season resulted in networks with both higher contact rates and higher potential for pathogen spread than in the wet season. Simulated disease outbreaks were also larger in the dry season. Results support the hypothesis that limited water resources enhance connectivity and transmission within contact networks, as opposed to reducing connectivity as a result of competitive avoidance. These results cast light on the impact of seasonal heterogeneity in resource availability on predicting pathogen transmission dynamics, which has implications for other free-ranging wild and domestic populations.

scholarly journals Analysis of Precipitation Extremes in the Source Region of the Yangtze River during 1960–2016

Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1691 ◽  
Author(s):  
Baojia Zhou ◽  
Chuan Liang ◽  
Peng Zhao ◽  
Qiong Dai
Keyword(s):  
Extreme Precipitation ◽  
Yangtze River ◽  
Source Region ◽  
Heavy Precipitation ◽  
Dry Season ◽  
Annual Maximum ◽  
The Yangtze River ◽  
Wet Season ◽  
Daily Precipitation Data ◽  
Increasing Trends

The source region of the Yangtze River (SRYR) on the central Tibetan Plateau has seen one of the most significant increases in temperature in the world. Climate warming has altered the temporal and spatial characteristics of precipitation in the SRYR. In this study, we analyzed the temporal trends and spatial distributions of extreme precipitation in the SRYR during 1960–2016 using 11 extreme precipitation indices (EPIs) derived from daily precipitation data collected at five meteorological stations in the region. The trends in the EPIs were estimated using the linear least squares method, and their statistical significance was assessed using the Mann–Kendall test. The results show the following. Temporally, the majority of SRYR EPIs (including the simple daily intensity index, annual maximum 1-day precipitation (RX1day), annual maximum 5-day precipitation (RX5day), very wet day precipitation, extremely wet day precipitation, number of heavy precipitation days, number of very heavy precipitation days, and number of consecutive wet days) exhibited statistically nonsignificant increasing trends during the study period, while annual total wet-day precipitation (PRCPTOT) and the number of wet days exhibited statistically significant increasing trends. In addition, the number of consecutive dry days (CDD) exhibited a statistically significant decreasing trend. For the seasonal EPIs, the PRCPTOT, RX1day, and RX5day all exhibited nonsignificant increasing trends during the wet season, and significant increasing trends during the dry season. Spatially, changes in the annual and wet season EPIs in the study area both exhibited significant differences in their spatial distribution. By contrast, changes in dry season PRCPTOT, RX1day, and RX5day exhibited notable spatial consistency. These three indices exhibited increasing trends at each station. Moreover, there was a statistically significant positive correlation between the annual PRCPTOT and each of the other EPIs (except CDD). However, the contribution of extreme precipitation to annual PRCPTOT exhibited a nonsignificant decreasing trend.

scholarly journals Modelling Climate Change Impacts on the Seasonality of Water Resources in the Upper Ca River Watershed in Southeast Asia

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Pham Quy Giang ◽  
Kosuke Toshiki ◽  
Masahiro Sakata ◽  
Shoichi Kunikane ◽  
Tran Quoc Vinh
Keyword(s):  
Climate Change ◽  
Water Resources ◽  
Southeast Asia ◽  
Swat Model ◽  
Dry Season ◽  
Global Climate Models ◽  
Wet Season ◽  
River Watershed ◽  
Ca River ◽  
The Impact

The impact of climate change on the seasonality of water resources in the Upper Ca River Watershed in mainland Southeast Asia was assessed using downscaled global climate models coupled with the SWAT model. The results indicated that temperature and evapotranspiration will increase in all months of future years. The area could warm as much as 3.4°C in the 2090s, with an increase of annual evapotranspiration of up to 23% in the same period. We found an increase in the seasonality of precipitation (both an increase in the wet season and a decrease in the dry season). The greatest monthly increase of up to 29% and the greatest monthly decrease of up to 30% are expected in the 2090s. As a result, decreases in dry season discharge and increases in wet season discharge are expected, with a span of ±25% for the highest monthly changes in the 2090s. This is expected to exacerbate the problem of seasonally uneven distribution of water resources: a large volume of water in the wet season and a scarcity of water in the dry season, a pattern that indicates the possibility of more frequent floods in the wet season and droughts in the dry season.

scholarly journals Seasonally Variant Stable Isotope Baseline Characterisation of Malawi’s Shire River Basin to Support Integrated Water Resources Management

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1410 ◽  
Author(s):  
Limbikani C. Banda ◽  
Michael Rivett ◽  
Robert Kalin ◽  
Anold Zavison ◽  
Peaches Phiri ◽  
...  
Keyword(s):  
Water Resources ◽  
Stable Isotope ◽  
River Basin ◽  
Water Resources Management ◽  
Integrated Water Resources Management ◽  
Lake Malawi ◽  
Dry Season ◽  
Diagnostic Tools ◽  
Wet Season ◽  
Resources Management

Integrated Water Resources Management (IWRM) is vital to the future of Malawi and motivates this study’s provision of the first stable isotope baseline characterization of the Shire River Basin (SRB). The SRB drains much of Southern Malawi and receives the sole outflow of Lake Malawi whose catchment extends over much of Central and Northern Malawi (and Tanzania and Mozambique). Stable isotope (283) and hydrochemical (150) samples were collected in 2017–2018 and analysed at Malawi’s recently commissioned National Isotopes Laboratory. Distinct surface water dry-season isotope enrichment and wet-season depletion are shown with minor retention of enriched signatures ascribed to Lake Malawi influences. Isotopic signatures corroborate that wet-season river flows mostly arise from local precipitation, with dry-season flows supported by increased groundwater contributions. Groundwater signatures follow a local meteoric water line of limited spread suggesting recharge by local precipitation predominantly during the peak months of the wet-season. Relatively few dry-season groundwater samples displayed evaporative enrichment, although isotopic seasonality was more pronounced in the lowlands compared to uplands ascribed to amplified climatic effects. These signatures serve as isotopic diagnostic tools that valuably informed a basin conceptual model build and, going forward, may inform key identified Malawian IWRM concerns. The isotopic baseline establishes a benchmark against which future influences from land use, climate change and water mixing often inherent to IWRM schemes may be forensically assessed. It thereby enables both source-water protection and achievement of Sustainable Development Goal 6.

scholarly journals THE DAILY RAINFALL STATISTICAL SHIFT DURING THE HALF CENTURY OVER THE BRANTAS CATCHMENT, EAST JAVA(STATISTIK PERUBAHAN CURAH HUJAN HARIAN SELAMA SETENGAH ABAD DI DAERAH TANGKAPAN BRANTAS, JAWA TIMUR)

Agromet ◽  
2007 ◽  
Vol 21 (1) ◽  
pp. 1
Author(s):  
E. Aldrian ◽  
F Ismaini ◽  
Yonny Koesmaryono
Keyword(s):  
Transition Period ◽  
Daily Rainfall ◽  
Kendall Test ◽  
Dry Season ◽  
Transitional Period ◽  
Quality Data ◽  
Trend Test ◽  
Wet Season ◽  
Rainy Days

<p>A study of long term shift of the daily rainfall over the Brantas catchment East Java was done. Such a study is relatively new for the country due to lack of good quality data and sparsely distributed data all over the region. With a good quality long-term daily rainfall data over the Brantas catchment, we could detect a statistical shift of amount of rainy days, shift between periods and frequency trend changes from weekly, monthly, three-monthly and annually. The study utilized several methods including the probability density function distribution shift, Mann Kendall non parametric trend test and the wavelet analyses. The shift of low amount rainfall occurs from the dry to the wet season. We found distinct influences of orography and ENSO years in our trend tests. Additionally, the result of the Mann Kendall test show that the trend of rainy days increase during the wet season and the second transition period, while decrease during the dry season and first transitional period. Meanwhile the El Nino and La Nina have significant influence toward the dry season and the second transitional period.</p>

scholarly journals The seasonal changes of the gut microbiome of the population living in traditional lifestyles are represented by characteristic species-level and functional-level SNP enrichment patterns

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Xue Zhu ◽  
Jiyue Qin ◽  
Chongyang Tan ◽  
Kang Ning
Keyword(s):  
Gut Microbiome ◽  
Seasonal Changes ◽  
Dry Season ◽  
Urban Setting ◽  
Snp Analysis ◽  
Wet Season ◽  
Human Gut ◽  
Human Gut Microbiome ◽  
Genome Level ◽  
Prevalent Species

Abstract Background Most studies investigating human gut microbiome dynamics are conducted on humans living in an urban setting. However, few studies have researched the gut microbiome of the populations living traditional lifestyles. These understudied populations are arguably better subjects in answering human-gut microbiome evolution because of their lower exposure to antibiotics and higher dependence on natural resources. Hadza hunter-gatherers in Tanzania have exhibited high biodiversity and seasonal patterns in their gut microbiome composition at the family level, where some taxa disappear in one season and reappear later. Such seasonal changes have been profiled, but the nucleotide changes remain unexplored at the genome level. Thus, it is still elusive how microbial communities change with seasonal changes at the genome level. Results In this study, we performed a strain-level single nucleotide polymorphism (SNP) analysis on 40 Hadza fecal metagenome samples spanning three seasons. With more SNP presented in the wet season, eight prevalent species have significant SNP enrichment with the increasing number of SNP calling by VarScan2, among which only three species have relatively high abundances. Eighty-three genes have the most SNP distributions between the wet season and dry season. Many of these genes are derived from Ruminococcus obeum, and mainly participated in metabolic pathways including carbon metabolism, pyruvate metabolism, and glycolysis. Conclusions Eight prevalent species have significant SNP enrichments with the increasing number of SNP, among which only Eubacterium biforme, Eubacterium hallii and Ruminococcus obeum have relatively high species abundances. Many genes in the microbiomes also presented characteristic SNP distributions between the wet season and the dry season. This implies that the seasonal changes might indirectly impact the mutation patterns for specific species and functions for the gut microbiome of the population that lives in traditional lifestyles through changing the diet in wet and dry seasons, indicating the role of these variants in these species’ adaptation to the changing environment and diets.

scholarly journals Seasonal Climate Impacts on Vocal Activity in Two Neotropical Nonpasserines

Diversity ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 319
Author(s):  
Cristian Pérez-Granados ◽  
Karl-L. Schuchmann
Keyword(s):  
Air Temperature ◽  
Daily Rainfall ◽  
Climatic Conditions ◽  
Dry Season ◽  
Climate Impacts ◽  
Calling Behavior ◽  
Wet Season ◽  
Focal Species ◽  
Calling Activity ◽  
Vocal Activity

Climatic conditions represent one of the main constraints that influence avian calling behavior. Here, we monitored the daily calling activity of the Undulated Tinamou (Crypturellus undulatus) and the Chaco Chachalaca (Ortalis canicollis) during the dry and wet seasons in the Brazilian Pantanal. We aimed to assess the effects of climate predictors on the vocal activity of these focal species and evaluate whether these effects may vary among seasons. Air temperature was positively associated with the daily calling activity of both species during the dry season. However, the vocal activity of both species was unrelated to air temperature during the wet season, when higher temperatures occur. Daily rainfall was positively related to the daily calling activity of both species during the dry season, when rainfall events are scarce and seem to act as a trigger for breeding phenology of the focal species. Nonetheless, air temperature was negatively associated with the daily calling activity of the Undulated Tinamou during the wet season, when rainfall was abundant. This study improves our understanding of the vocal behavior of tropical birds and their relationships with climate, but further research is needed to elucidate the mechanisms behind the associations found in our study.

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