scholarly journals Specific changes in main climatic characteristics of the Debed river basin (Armenia)

Formulation of the problem. The article discusses changes in the main climatic characteristics in the Debed river basin (Armenia) at six meteorological stations. The aim of the work is to analyze and assess peculiar territorial distribution of the main climatic indicators in the Debed river basin, their changes over the past 80-90 years in different conditions of Armenia. Methods. To solve the set tasks, the authors used corresponding research and published works as a theoretical basis in the work. As a starting material, the work used the daily factual data of the "Center for Hydrometeorology and Monitoring" of the SNCO, Ministry of Environment of the Republic of Armenia for the period from 1930 to 2018 at six meteorological stations. The authors applied the following research methods in the article: mathematical and statistical, extrapolation, analysis, analogy, correlation, cartographic. Results. Climate of the earth has been changing rapidly over the past decades, leading to global warming. As a result, we are facing the problem of assessing the macroeconomic consequences of climate change in this territory. Armenia did not remain aloof from the problems of global climate change. On the territory of the river Debed's basin air temperature distribution and precipitation is uneven, due to the geographical latitude of the area, general and local circulation of the atmosphere, radiation energy and orographic features. We notice a decrease in air temperature and an increase in precipitation with the height of the terrain and the vertical gradient, respectively, is 0.54 ºC / 100 m and -20 mm / 100 m. The average annual air temperature ranges from 3.74 ºC to 12.3 ºC, and the annual precipitation is from 462 mm to 770 mm. Studies have also shown that long-term fluctuations in average air temperature over the year are generally characterized by positive trends. Air temperature in the basin of the river Debed increased by 1.65 °С on average over the year from 1964 to 2018. A particularly significant increase in annual temperatures has been observed after the 1990s, when the rate of annual warming reached +0.389 ºС / 10 years (for the period 1993-2018). The warmest years were 1966, 2010 and 2018. The tendency towards a decrease in the annual amount of precipitation prevails in the area. The most significant amount of precipitation decreased in the basin of the river Debed after 2002. The rate of changes in the annual amount of atmospheric precipitation for the period 2002–2018 reached -61.7 mm / 10 years, and for the entire period 1964-2018 - 1.02 mm / 10 years. On average a decrease in annual precipitation was 126 mm from 1964 to 2001, 105 mm - from 2002 to 2018 in the basin of the river Debed. There is a tendency for a slight increase in the amount of precipitation at the Stepanavan weather station.

2020 ◽  
Vol 149 ◽  
pp. 03010
Author(s):  
Varduhi Margaryan ◽  
Elena Fedotova

The paper analyzes the peculiarities of formation of the absolute maximum runoff of the Marmarik river evaluates the patterns of multi-year fluctuations of maximum runoff rates in different river sites and gives a forecast of the maximum runoff in the context of global climate change. Absolute values of the maximum river runoff for different scenarios of climate change are estimated. The actual observational data of Armhydromet for maximum runoff rate, the air temperature and precipitation were used as the source material. As a result of the study, it turned out that there is only a tendency to decrease in the values of maximum runoff. It turned out that for all scenarios and cases in the Marmarik river basin, a different degree of changes in the maximum flow is observed. Moreover, the largest decrease in the maximum runoff of the Marmarik river basin is expected under the conditions of an increase in the average air temperature of the spring season by 2,7—3,9 degrees Celsius and a decrease in the amount of spring atmospheric precipitation by 2,4—2,6 %.


2021 ◽  
Author(s):  
Hanna Bolbot ◽  
Vasyl Grebin

<p>The current patterns estimation of the water regime under climate change is one of the most urgent tasks in Ukraine and the world. Such changes are determined by fluctuations in the main climatic characteristics - precipitation and air temperature, which are defined the value of evaporation. These parameters influence on the annual runoff distribution and long-term runoff fluctuations. In particular, the annual precipitation redistribution is reflected in the corresponding changes in the river runoff.<br>The assessment of the current state and nature of changes in precipitation and river runoff of the Siverskyi Donets River Basin was made by comparing the current period (1991-2018) with the period of the climatological normal (1961-1990).<br>In general, for this area, it was defined the close relationship between the amount of precipitation and the annual runoff. Against the background of insignificant (about 1%) increase of annual precipitation in recent decades, it was revealed their redistribution by seasons and separate months. There is a decrease in precipitation in the cold period (November-February). This causes (along with other factors) a decrease in the amount of snow and, accordingly, the spring flood runoff. There are frequent cases of unexpressed spring floods of the Siverskyi Donets River Basin. The runoff during March-April (the period of spring flood within the Ukrainian part of the basin) decreased by almost a third.<br>The increase of precipitation during May-June causes a corresponding (insignificant) increase in runoff in these months. The shift of the maximum monthly amount of precipitation from May (for the period 1961-1990) to June (in the current period) is observed.<br>There is a certain threat to water supply in the region due to the shift in the minimum monthly amount of precipitation in the warm period from October to August. Compared with October, there is a higher air temperature and, accordingly, higher evaporation in August, which reduces the runoff. Such a situation is solved by rational water resources management of the basin. The possibility of replenishing water resources in the basin through the transfer runoff from the Dnieper (Dnieper-Siverskyi Donets channel) and the annual runoff redistribution in the reservoir system causes some increase in the river runoff of summer months in recent decades. This is also contributed by the activities of the river basin management structures, which control the maintenance water users' of minimum ecological flow downstream the water intakes and hydraulic structures in the rivers of the basin.<br>Therefore, in the period of current climate change, the annual runoff distribution of the Siverskyi Donets River Basin has undergone significant changes, which is related to the annual precipitation redistribution and anthropogenic load on the basin.</p>


2010 ◽  
Vol 14 (10) ◽  
pp. 1979-1987 ◽  
Author(s):  
J. Wang ◽  
H. Li ◽  
X. Hao

Abstract. The spatial and temporal variations of snowcover distribution, and snowmelt runoff are considered as sensitive indicators for climatic change. The purpose of this paper is to analyze and forecast the responses of snowmelt runoff to climate change in an inland river basin. The upper basin of Heihe River in Northwestern China was chose as the study area, and the observation data from the meteorological and hydrological stations were utilized to analyze the status and regularity of the climatic change over the past 50 years. Snow cover area was obtained by an optimized technology using Moderate Resolution Imaging Spectroradiometer data with Normalized Difference Snow Index adjustment and topographic correction. A concept of potential snowmelt was suggested to illustrate the response of spatial snowmelt to climate change. The results show that the annual SCA proportion and the potential snowmelt keep an increasing trend since 2000. There is a negative relationship between annual air temperature and SCA proportion from 2000 to 2008. Snowmelt Runoff Model was chose to simulate snowmelt runoff and scenario forecast the change trend of snowmelt runoff in this region. The results show that climatic warming was apparent in the upper basin of Heihe River over the past 50 a. Annual average air temperature of three different weather stations located in the basin has increased 2.1 °C, 2.6 °C and 2.9 °C respectively from 1956 to present. The snowmelt runoff has increased obviously from 1970 to present. With different warming climate scenarios, the results by using SRM simulating showed that the first occurred time of snowmelt runoff shift ahead and discharge become larger as responses of snowmelt runoff to air temperature increasing, and the influence of temperature rising on average discharge of the whole snow season is not obvious.


Author(s):  
V. Khokhlov ◽  
N. Yermolenko

Global climate change has provoked an active development in modern methods relating to the prediction of spatiotemporal hydrometeorological fields. Numerical modeling of nearest-future climatic changes allows to generate strategies of development for different areas of economic activity. The paper aims to assess the expected air temperature and precipitation features in Ukraine considering different scenarios of climatic change. The modeling future changes of air temperature and precipitation were carried out using the A1B and A2 scenarios of climatic change. The outcomes of regional climate model ECHAM5 from ENSEMBLES Project were used as initial data. It was revealed that the air temperature will gradually increase in most of Ukrainian regions. Moreover highest air temperature will be recorded in Southern Ukraine during 2031-2050. The analysis of linear trends for 2031-2050 showed that the air temperature for the scenario A1B will exhibit a tendency to the decrease of temperature. However, the annually mean temperature in 2031-2050 for the ‘moderate’ scenario A1B will be higher than for the ‘hard’, in terms of greenhouse gases concentrations, scenario A2. The annual precipitation in Ukraine, both for the A1B and A2 scenario, will slightly increase toward the 2050 with the exception of Southern Ukraine. Also, the highest annual precipitation will be registered in the western part of Ukraine, and lowest – in the southern one. The paper can be expanded to the analysis of future dangerous weather phenomena depending on the changes of air temperature and precipitation.


Author(s):  
O. Obodovskyi ◽  
V. Grebin ◽  
S. Snizhko ◽  
I. Kuprikov ◽  
O. Shevchenko Shevchenko

This article presents the results of the verification of the homogeneity of the data of long-term observations on the average annual air temperature and annual precipitation amounts according to the data of 143 meteorological stations operating on the territory of Ukraine to date and have a long (in the vast majority of cases, more than 55-60 years) rows of observations within 14 areas of river basins and sub-basins that have been allocated within the country for research. To do this, the parametric criteria of Student and Fischer, as well as the non-parametric Wilcoxon criterion, were used. Briefly described these three criteria and statistical methods for assessing the homogeneity of hydrological and meteorological sequences in general. The basic concepts of mathematical statistics, such as the null hypothesis, the statistical criterion, the level of significance, the critical area, are deciphered. The number of used meteorological stations for each of the selected areas of river basins and sub-basins was determined. The heterogeneity of the series of average annual air temperature for all 14 selected areas of river basins and sub-basins was revealed. The rows of the long-term course of average annual air temperatures are homogeneous only at two meteorological stations within the boundaries of the Crimean river basin districts (Simferopol and Dzhankoy). Significant homogeneity of the rows of annual precipitation amounts for the overwhelming majority of areas of river basins and sub-basins was also revealed. It is noted that for five of the studied areas of river basins and sub-basins, the homogeneity index is 100 % for all three of the involved criteria of mathematical statistics. The lowest index of homogeneity of the rows of annual rainfall amounts is typical for the Wisla River basin district, where it is 60 %. This is one of the smallest selected areas, which occupies a very small area within Ukraine (about 4 %). The following conclusions are made: 1. The indices of homogeneity of the rows of annual precipitation amounts received for the territory of Ukraine according to 143 meteorological stations indicate that there are no directed changes in annual rainfall in most of the country. 2. The indices of homogeneity of the series of average annual values of air temperatures obtained for the territory of Ukraine according to the data of the same 143 meteorological stations according to different criteria testify to the violation of the homogeneity of this indicator on the territory of Ukraine since about 1989, which testifies to the climatic changes taking place in the country over the past decades, reflecting global climate change.


2021 ◽  
Vol 14 (1) ◽  
pp. 196-208
Author(s):  
Trahel G. Vardanyan ◽  
Natalia L. Frolova ◽  
Hrachuhi S. Galstyan

The study concerned the analysis of temporal and spatial variability of floods in the Republic of Armenia (RA). While there are number of reports on flood formation of rivers in RA, the literature lacks results on using nonparametric test results to analyze this disastrous phenomenon. For that purpose, the dynamics of changes in extreme maximum instantaneous runoff, as well as air temperature and precipitation database was evaluated and compared between 1960–2012 for 27 hydrometrical observational and 35 meteorological stations in RA. The Mann-Kendall test with consideration of the autocorrelation function was employed as a non-parametric testto identify any present trends. An increasing tendency of air temperature, decreasing tendency of the atmospheric precipitation and extreme maximum instantaneous river runoff were identified in the studied river-basins. As expected, the warming climate contributed to a gradual melting of accumulated snow in the river-basins in winter, resulting in changes in the extreme maximum instantaneous runoff of the rivers in spring, which significantly reduces the risk of the flood occurrence. Thus, it can be claimed that almost all the river basins of Armenia have a tendency to reduce the risk of floods due to global climate change.


2021 ◽  
Vol 25 (5) ◽  
pp. 65-71
Author(s):  
V.V. Drozdov ◽  
G.T. Frumin ◽  
A.V. Kosenko

The review and analysis of the long-term variability of the average annual and average air temperature for winter and summer, as well as the values of the amounts of atmospheric precipitation in St. Petersburg were carried out. The correlation between the dynamics of the values of these indicators and the intensity of atmospheric circulation over the North Atlantic in the form of the NAO1 index (North Atlantic Oscillation) was estimated. The possible environmental consequences of climate change in the region of St. Petersburg are justified.


Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1962
Author(s):  
Zhilong Zhao ◽  
Yue Zhang ◽  
Zengzeng Hu ◽  
Xuanhua Nie

The alpine lakes on the Tibetan Plateau (TP) are indicators of climate change. The assessment of lake dynamics on the TP is an important component of global climate change research. With a focus on lakes in the 33° N zone of the central TP, this study investigates the temporal evolution patterns of the lake areas of different types of lakes, i.e., non-glacier-fed endorheic lakes and non-glacier-fed exorheic lakes, during 1988–2017, and examines their relationship with changes in climatic factors. From 1988 to 2017, two endorheic lakes (Lake Yagenco and Lake Zhamcomaqiong) in the study area expanded significantly, i.e., by more than 50%. Over the same period, two exorheic lakes within the study area also exhibited spatio-temporal variability: Lake Gaeencuonama increased by 5.48%, and the change in Lake Zhamuco was not significant. The 2000s was a period of rapid expansion of both the closed lakes (endorheic lakes) and open lakes (exorheic lakes) in the study area. However, the endorheic lakes maintained the increase in lake area after the period of rapid expansion, while the exorheic lakes decreased after significant expansion. During 1988–2017, the annual mean temperature significantly increased at a rate of 0.04 °C/a, while the annual precipitation slightly increased at a rate of 2.23 mm/a. Furthermore, the annual precipitation significantly increased at a rate of 14.28 mm/a during 1995–2008. The results of this study demonstrate that the change in precipitation was responsible for the observed changes in the lake areas of the two exorheic lakes within the study area, while the changes in the lake areas of the two endorheic lakes were more sensitive to the annual mean temperature between 1988 and 2017. Given the importance of lakes to the TP, these are not trivial issues, and we now need accelerated research based on long-term and continuous remote sensing data.


Atmosphere ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 987
Author(s):  
Mana Raj Rai ◽  
Amnat Chidthaisong ◽  
Chaiwat Ekkawatpanit ◽  
Pariwate Varnakovida

The Himalayas, especially the Everest region, are highly sensitive to climate change. Although there are research works on this region related to cryospheric work, the ecological understandings of the alpine zone and climate impacts are limited. This study aimed to assess the changes in surface water including glacier lake and streamflow and the spatial and temporal changes in alpine vegetation and examine their relationships with climatic factors (temperature and precipitation) during 1995–2019 in the Everest region and the Dudh Koshi river basin. In this study, Landsat time-series data, European Commission’s Joint Research Center (JRC) surface water data, ECMWF Reanalysis 5th Generation (ERA5) reanalysis temperature data, and meteorological station data were used. It was found that the glacial lake area and volume are expanding at the rates of 0.0676 and 0.0198 km3/year, respectively; the average annual streamflow is decreasing at the rate of 2.73 m3/s/year. Similarly, the alpine vegetation greening as indicated by normalized difference vegetation index (NDVI) is increasing at the rate of 0.00352 units/year. On the other hand, the annual mean temperature shows an increasing trend of 0.0329 °C/year, and the annual precipitation also shows a significant negative monotonic trend. It was also found that annual NDVI is significantly correlated with annual temperature. Likewise, the glacial lake area expansion is strongly correlated with annual minimum temperature and annual precipitation. Overall, we found a significant alteration in the alpine ecosystem of the Everest region that could impact on the water–energy–food nexus of the Dudh Koshi river basin.


Author(s):  
Partha Sarathi Datta

In many parts of the world, freshwater crisis is largely due to increasing water consumption and pollution by rapidly growing population and aspirations for economic development, but, ascribed usually to the climate. However, limited understanding and knowledge gaps in the factors controlling climate and uncertainties in the climate models are unable to assess the probable impacts on water availability in tropical regions. In this context, review of ensemble models on δ18O and δD in rainfall and groundwater, 3H- and 14C- ages of groundwater and 14C- age of lakes sediments helped to reconstruct palaeoclimate and long-term recharge in the North-west India; and predict future groundwater challenge. The annual mean temperature trend indicates both warming/cooling in different parts of India in the past and during 1901–2010. Neither the GCMs (Global Climate Models) nor the observational record indicates any significant change/increase in temperature and rainfall over the last century, and climate change during the last 1200 yrs BP. In much of the North-West region, deep groundwater renewal occurred from past humid climate, and shallow groundwater renewal from limited modern recharge over the past decades. To make water management to be more responsive to climate change, the gaps in the science of climate change need to be bridged.


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