Water Balance Values Research Articles

ANALISIS KETERSEDIAAN AIR SAWAH TADAH HUJAN DI KELURAHAN KARYA MULIA KECAMATAN SEMATANG BORANG KOTA PALEMBANG

Rice fields that rely mostly on rainwater for irrigation are known as rainfed rice fields. Only the wet season yields rice fields like this one. Because of the heavy rains throughout the rainy season, agricultural land's water supply is not a concern. But during the dry season, when the water supply is getting smaller, the requirement for water for plants becomes a complex issue. This study aims to find out whether the rainfall currently available can satisfy the water needs of rainfed rice fields in Karya Mulia Village, Sematang Borang District, Palembang City, and to optimize the water supply. The following was discovered by the study's findings: water balance of discharge of water availability and water requirement for rainfed rice fields in Karya Mulia Village, which has a land area of 58 Ha, there is a water balance value of 23.711 mm per hari, which meets the water balance requirement for one growing season of rice plantsIn order to be optimal in the second growing season, it can be planted with crops that balance the availability and water demand at 10.844 mm/day.

Estimating the costs of managed aquifer recharge under uncertainty with examples for town water supply in regional Australia

HighlightsCost distribution curves for well injection and infiltration basin recharge schemes.Probabilistic, time-varying, coupled water balance and net present value modelling.Disaggregated capital and operating expenses and global sensitivity analyses.Examples for increasing regional area town water security in Australia’s Murray Darling Basin.

Analisis Pengaruh Ketersediaan Air Permukaan Terhadap Debit Mata Air

Springs are one of the water sources that people can use to meet their clean water needs. The Balinese people in particular, apart from using spring water to fulfill their daily needs, also use it as a means of religious ceremonies so that its sustainability is strictly maintained. One of the springs that can be found in Bali is the Tirta Salaka spring. Tirta Salaka spring is located in Sading Village, Mengwi District, Badung Regency, Bali Province. The purpose of this study was to analyze the effect of surface water availability on Tirta Salaka springs. The method used in the research is a combination of quantitative and analytical methods. Based on calculations, the discharge value of the Tirta Salaka spring is smaller than the general water balance value from November to March. The discharge value of the Tirta Salaka spring from November 2022 to March 2023 is included in class VI with values of 1.111.931 liters/month, 1.196.208 liters/month, 1.413.677 liters/month, 1.036.800 liters/month, and 914.717 liters/month. This shows that the amount of discharge from the Tirta Salaka spring is influenced by rainfall. The higher the rainfall value, the higher the discharge of the Tirta Salaka spring

Large-scale water balance modeling using remote sensing and weather data: Application in an agricultural growing region of the coastal northeast Brazil

The SAFER (Simple Algorithm for Evapotranspiration Retrieving) algorithm was applied to test water balance (WB) monitoring in the agricultural growing region of SEALBA, an acronym for the states Sergipe (SE), Alagoas (AL), and Bahia (BA), coastal Northeast Brazil, classifying the biomes Atlantic Forest and Caatinga. The MODIS MOD13Q1 reflectance product and meteorological data were used to calculate actual (ET) and reference (ET0) evapotranspiration at 16-day timescale along the years 2007–2021. The period with the highest precipitation (P) is in May, when the 16-day values are above 90 mm in Atlantic Forest and higher than 70 mm in Caatinga. For ET, the largest rates occur between July and September, when the 16-day average surpass 2.70 mm d−1 in the Atlantic Forest and 2.90 mm d−1 in Caatinga. Larger P together with lower ET, concentrates the positive water balance - WB (P – ET) from March to August in both biomes, bringing suitability for the rainfed agriculture. However, from July to December occur the negative WB values, indicating the need of irrigation for critical crop stages. Inferring the root-zone moisture conditions throughout the evaporative fraction values (ETf = ET/ET0) it is noticed that their highest values occur from April to October, evidencing a delay between the moment in which rainfall attend evapotranspiration with that in which the root-zone moisture recovers the optimum levels after the driest periods, what was also confirmed by the Pearson correlation coefficient values. The large-scale modelling carried out in SEALBA, presented viability to subsidize public policies regarding the water resources, with potential for replication of the methods in other regions.

Climate risk zoning for wheat crops in the southeastern region of Brazil.

Wheat (Triticum aestivum L.) is the second most consumed food in the world. One way to meet this demand is the expansion of wheat cultivation to the Brazilian Cerrado in the southeastern region. However, one of the major limitations is that there are few studies related to wheat climate risk zoning. Thus, this study aimed to determine the agroclimatic zoning of wheat by estimating the water needs satisfaction index (ISNA) in the southeastern region of Brazil. For this purpose, a 60-year historical series of meteorological data was used to calculate the potential evapotranspiration, crop evapotranspiration, and climatological water balance values. To define the agroclimatic zones of wheat and sowing date, the ISNA method was used. The data were analyzed using descriptive statistics to determine the variations. To obtain the agroclimatic zoning of wheat, the geostatistical method of kriging interpolation was used. The regions with the highest rainfall are the south of Minas Gerais and the coast of São Paulo. The sowing period directly impacts the development of the crop, the available water capacity and the ISNA values indicated the spring and summer had better cultivation conditions, and the best window for wheat cultivation is concentrated in the fall due to the limitation of biotic factors. In terms of altitude (>700 m), Minas Gerais has 39.4% of the area suitable for wheat cultivation. Thus, climatic variations within and between the states of the southeastern region should be considered for the positioning of wheat cultivars in these regions to obtain the maximum yield. © 2023 Society of Chemical Industry.

Improved Representation of Groundwater–Surface Water Interactions Using SWAT+gwflow and Modifications to the gwflow Module

Recent water availability and scarcity problems have highlighted the importance of surface–groundwater interactions. Thus, groundwater models are coupled with surface water models. However, this solution is complex, needing code modifications and long computation times. Recently, a new groundwater module (gwflow) was developed directly inside the SWAT code to tackle these issues. This research assesses gwflow’s capabilities in representing surface–groundwater system interactions in the Dijle catchment (892.54 km2), a groundwater-driven watershed in Belgium. Additional developments were made in SWAT+gwflow to represent the interaction between the groundwater and soil (gwsoil). The model was calibrated for monthly mean streamflow at the catchment outlet (1983 to 1996) and validated for two periods (validation 1: 1975 to 1982 and validation 2: 1997 to 2002). It was found that the SWAT+gwflow model is better at representing the total flow (NSE of 0.6) than the standalone SWAT+ (NSE of 0.4). This was confirmed during two validation periods where the standalone model scored unsatisfactory monthly NSE (0.6 and 0.1), while the new model’s NSE was 0.7 and 0.5. Additionally, the SWAT+gwflow model simulations better depict the groundwater via baseflow and attain proper water balance values. Thus, in a highly groundwater-driven catchment, the simplified representation of groundwater systems by the standalone SWAT+ model has pitfalls. In addition, the modification made to the gwflow module (gwsoil) improved the model’s performance, which, without such adjustment, overestimates the streamflow via saturation excess flow. When including the gwsoil mechanism, thereby providing a more accurate representation of water storage and movement, groundwater is transferred to the soil profile, increasing the overall soil water content and thereby increasing lateral flow. This novel modification can also have implications for other distributed hydrological models to consider such exchanges in their modeling scheme.

Herbaceous Peony Polyphenols Extend the Vase Life of Cut Flowers

Herbaceous peony is a potential material for cut flowers, but its short vase life seriously affects the development of cut herbaceous peony flowers industry. In this study, herbaceous peony polyphenols were applied to extend the vase life of cut flowers, and the results indicated that 8% mass concentration of herbaceous peony polyphenols increased the superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities; increased the soluble protein content of the cut flowers; and effectively reduced the malondialdehyde (MDA) content. Meanwhile, herbaceous peony polyphenols increased the water balance value of cut flowers. In addition, the observation of microstructures indicated that herbaceous peony polyphenols reduced the blockage mainly caused by Aspergillus spp. at the stem ends and inhibited the growth of Aspergillus spp. Additionally, aquaporin genes (AQPs), including three plasma membrane intrinsic protein genes (PlPIP1;2, PlPIP2;1, and PlPIP2;2) and one intrinsic protein gene (PlNIP), were isolated. PlPIP1;2, PlPIP2;1, and PlPIP2;2, which were induced by polyphenol treatment, had common effects on maintaining the water balance of cut flowers. Therefore, herbaceous peony polyphenols can significantly extend the vase life of cut flowers; these results provide for the application of the theoretical reference of herbaceous peony polyphenols in extending the vase life of cut flowers.

Sodium selenite improves the vase life of Eustoma grandiflorum cut flowers

Previous studies indicated that the antioxidant and water balance capacity played important roles in improving the vase life of cut flowers. As a trace element, selenium (Se) has been proven to play an important role in extending the vase life of lily cut flowers. However, there is still no report on the effects of Se on the vase life of other cut flowers. In this study, we explored the role of inorganic selenium, named sodium selenite (Na2SeO3), in improving the vase life of Eustoma grandiflorum cut flowers. Compared with the control (distilled water) and the other Na2SeO3 concentrations, 4.0 mg/L Na2SeO3 significantly increased the superoxide dismutase, catalase, ascorbate peroxidase glutathione reductase, glutathione peroxidase and glutathione S-transferase activities, and decreased the malondialdehyde content and the electrolyte leakage. Meanwhile, compared with the control and the other of Na2SeO3 concentrations, 4.0 mg/L Na2SeO3 significantly increased the soluble sugar, proline and soluble protein contents, relative water content, average fresh weight change rate and average water balance value. The above results imply that Na2SeO3 showed an important role in strengthening the antioxidant capacity and maintaining the water balance. Besides, 4.0 mg/L Na2SeO3 significantly increased the flower diameter and the vase life. The above findings suggested that Na2SeO3 extended the vase life and the ornamental value of E. grandiflorum cut flowers by enhancing the antioxidant capacity and water balance, which provides new knowledge for the application of Na2SeO3 in improving the fresh keeping of E. grandiflorum cut flowers.

Water Balance Evaluation for Flood Risk Reduction in the Yala River Basin, Western Kenya

The Yala River Basin (YRB) in Western region of Kenya has in the past experienced climate and weather extreme events that include floods. Floods have triggered loss of lives, destruction of property, outbreak of water borne diseases and siltation of arable land. This study utilized the Nedbør-Afstrømnings-Model (NAM) hydrologic model (available in the NAM Module of the MIKE 11 hydrodynamic model) on the Yala River Basin (YRB) to generate flood flows for water balance evaluation. The study utilized satellite imagery data for the period 1984-2010 sourced from the Regional Centre for Mapping of Resources for Development, rainfall (1980-2012) and river discharge (1947-2012) data sets from the Kenya Meteorological Department (KMD) and the Water Resources Management Authority (WARMA), respectively. Data quality control was statistically checked before sensitivity analysis, calibration, validation, and simulation of the flood flows. Daily water balance estimates for the Yala River Basin (YRB) over the period 1980-2010 were developed using the NAM hydrologic model. The results indicate that the mapped flood area extent varied by a value of 34.23 km2 over the period 1980-2010. The Yala River Basin (YRB) indicated an estimated inflow value of 4,814.72 MCM and outflow value of 4,578.23 MCM, with a coefficient of determination of 0.867. The difference between the inflow and outflow values was 236.49 MCM, that formed the flood flow or the water balance. This study concluded that the water balance value of 236.49 MCM was responsible for the floods recorded in the Yala River Basin (YRB) for the period 1980-2010, and it should be taken care of through flood risk reduction initiatives.

SUSTAINABLE WATER AVAILABILITY MODEL WITH RESERVOIR TECHNIQUE BY USING ISM (INTERPRETATIVE STRUCTURAL MODELING) METHOD IN BANGKA ISLAND INDONESIA

The reduced of clean water availability is a problem in almost all parts of the world. This condition is caused by many factors such as population growth, industrialization, urbanization, transportation, etc. The same thing happened in Bangka Island. Based on the research conducted by Hambali (2013) the water balance in Pangkal Pinang was in poor condition (>100%) with a water balance value of 388.13% in 2013, 454% in 2018 and 531.04% in 2023. As the condition of the reduced of clean water availability, especially in Bangka Island, it is necessary to have alternative in providing clean water from other sources as an effort to conserve water to maintain the availability of clean water. One of the water conservation efforts that can be done to maintain the availability of clean water is by using rain harvesting technique. Rainfall source in Bangka Island is possible at reservoir(kulong/embung) of tin mining that has been done. By using the Interpretative Structural Modeling method, it is possible to obtain factor element, institutional element and actor element in sustainable water availability with reservoir technique in Bangka Island. Three key elements were found, namely institutional, social and environmental. Furthermore, the three main institutional elements were 1) regulatory context. 2) trust in community development and 3) positive relation with the community. Meanwhile, the 3 key actors were 1) Technical institution/unit. 2) Financial Institution and 3) Department of Public Works and Housing

Modelling the applicability of Low Impact Development (LID) technologies in a university campus in the Philippines using Storm Water Management Model (SWMM)

Progressive land development increases the imperviousness of an area which disrupts the water balance and results to the degradation of water quality, high peak flow, and excessive volume of surface runoff. One efficient approach to address this issue on water is the application of Low impact development (LID) technologies. LID helps improve the water quality and water quantity of an area to maximize its land-use. In this study, the eight LID technologies available in SWMM namely, bio retention cell, infiltration trench, rain garden, green roof, permeable pavement, rain barrel, rooftop disconnection, and vegetative swale were applied in simulating the area of the De La Salle University - Laguna Campus, a pre-developed area in Binan, Laguna which currently undergoes land-use change. This study area was simulated without the use of LID, with the use of varying LID, and capturing the 80, 90, and 95 percent of all the rainfall from 1989-2018. Digital elevation model and disaggregated rainfall data were used as input in SWMM. The ArcMap 10.4 was utilized to delineate and produce the three sub catchments with an area of 24.13 ha., 10.18 ha., and 4.34 ha., respectively while Storm Water Management Model (SWMM) software was used in analyzing these sub catchments to produce water balance values. Results showed that more than 60 percent of the disaggregated rainfall was under the one-year return period. Also, bioretention cell with 80th percentile rainfall maximizes the reduction of runoff while infiltration trenches with 95th percentile rainfall were the most effective in increasing the infiltration among the eight LID technologies. It was also indicated that the surface runoff in first sub catchment was reduced to more than 80% using bioretention cell, infiltration trench, rain garden, or rooftop disconnection. Finally, the area of a sub catchment has a positive correlation in its reduced runoff while a negative correlation in its infiltration when integrating the LID technologies. This research can be a resource for further studies and in to support SDGs 6, 9, and 11 to have a better water management, resilient infrastructures, and attain sustainable cities and communities.

The utility of climatic water balance for ecological inference depends on vegetation physiology assumptions

AbstractBackgroundIn explaining and predicting spatial vegetation patterns, ecologists have increasingly favoured the use of climatic water balance variables, including actual evapotranspiration (AET) and climatic water deficit (CWD), for representing the hydrologic and energetic environment experienced by plants. Much of the interest in these variables lies in their hypothesized potential to characterize biologically relevant environmental variation more directly than simple climate variables, such as precipitation and temperature. Practically, obtaining AET and CWD values across space requires hydrologic process models that involve assumptions, including assumptions about vegetation transpiration rates. However, transpiration parameter values are rarely known with precision and can vary several‐fold within and among vegetation types.ApproachWe evaluate the extent to which assumptions about vegetation physiology in water balance models affect (a) relative spatial variation in modelled water balance values and (b) ecological inferences that are derived from analyses using water balance variables. We demonstrate an approach for identifying inferences that are robust to these assumptions.ResultsAssumptions about vegetation physiology can substantially affect relative spatial variation in modelled water balance values. More importantly, such assumptions can also substantially affect the inferences (e.g., expected vegetation distributions) drawn from ecological analyses that use water balance variables as predictors. Water balance variables are less sensitive to assumptions in environmental settings with abundant water supply, where AET variation is driven primarily by available energy (e.g., temperature and insolation), but they can be highly sensitive to assumptions in drier environments.ConclusionBecause of their sensitivity to assumptions, water balance variables are not unambiguously superior to simpler climatic and topographic variables, such as precipitation and temperature. However, they retain some advantages, primarily related to their mechanistic incorporation of interactions between water and energy, which may support their use in applications where sensitivity to hydrologic modelling assumptions is low or of minor concern.

Современные тенденции изменчивости климатических характеристик в районе Махачкалы и гидрологические последствия для Туралинских озер

Within the limits of a century-long weakly positive trend of air temperature in the surface layer, periods of increased and decreased values of temperature, precipitation, air humidity, evaporation, water balance and moisture coefficient of the average for the year and individual seasons are highlighted. For this purpose, absolute and cumulative deviation values of characteristics are used. The results show, that the forecast of an acceleration of the rate of warming in the twenty-first century proved to be correct. The last cycle, which began in 2010-2012, is characterized by the most rapid increase in climate factors, that exacerbate the negative water balance in comparison with previous periods. This leads to the drying up of the Turaly lakes located on the southern side of the Makhachkala-Caspian agglomeration. The obtained results call into question the possibility and feasibility of using dry estuaries as water bodies for fish farming.

Climate change and economic efficiency of agricultural production in the Steppe zone

Relevance of research. Due to ongoing climate change, almost the entire territory of the Steppe of Ukraine by annual humidity factor belongs to the dry and very dry zones, the relative area of ​​which has increased by 13.2% of the total area of ​​the country compared to the 1960-1990s. At the same time, for today in Ukraine only about 500 thousand hectares are actually irrigated, that is 19% of the potential area.
 Purpose of research. To determine the patterns and trends of climate change in the western part of the dry Steppe of Ukraine and analyze the economic indicators of production activity in the region as to the variable weather conditions.
 Research methodology. Climate change was estimated on the basis of Climate Water Balance (CWB) and Hydrothermal Coefficient (HTC) values. The analysis of the economic efficiency of agricultural production was carried out by analyzing the statistical data for Odessa region and for the chosen agricultural enterprise.
 Research results and conclusions. The use of significant heat supply in the dry Steppe zone is limited by insufficient water supply conditions. In the years of 1991-2016 the average annual rainfall was 480 mm and since the early 2000s there has been a slight increase in that. However, even having 500-550 mm of average annual rainfall that has been observed over the past five years, it is not enough for providing high-yield agricultural production. High thermal regime couses high evaporation that in turn, leads to water supply deficit, which at the end of the growing season amounts to 336-436 mm. According to the HTC index in the region 80% of cases show severe and moderately arid vegetation conditions. At the same time, irrigation area in the region has decreased to a minimum, which has led to the domination of winter cereals and sunflower in the cropping system. Under variable weather conditions, winter wheat yields ranged from 19.4 to 38.5 c/ ha (31.4 c/ha on average) and sunflower - from 12.2 to 21.4 c/ha (17.4 c/ha on average), winter rape - from 13.1 to 20.9 c/ha (18.2 c/ha). It was proved a close direct relationship between the sale price of products of all studied crops and their cost price, as well as the inverse relationship of these indicators with the crop yield. The profitability of winter wheat from 2011 till 2016 ranged from 17 to 153 USD/ha with an average value of 86 USD/ha, winter rape - from 39 to 273 USD/ha with an average value of 166 USD ha and sunflower - from 116 to 315 USD/ha with an average value of 192 USD/ha. Corn and soybeans have proven to be unprofitable in some years, which obviously explains rather small areas under these crops in the region.
 Above mentioned demonstrates the high economic instability of agricultural production in changing weather conditions, which is accompanied by significant risks for producers, especially when attracting credits. This situation, in turn, leads to a limited use of intensification means, in particular mineral fertilizers, which promotes agrochemical soil degradation. Under unstable water supply, the magnitude of net profit variation per hectare of arable land in Odessa region is 33-188 USD/ha (111 USD/ha on average). It is possible to increase these indicators by increasing the share of winter rape in the cropping system. With the optimization of the water and air soil regimes as well as crop rotation factor, the profitability of agricultural production in the region can be increased up to 580-600 USD/ha. Similar results were obtained after analyzing the statistical data from the southern regions within the dry steppe zone.

Carabus Population Response to Drought in Lowland Oak Hornbeam Forest

Forest management practices and droughts affect the assemblages of carabid species, and these are the most important factors in terms of influencing short- and long-term population changes. During 2017 and 2018, the occurrences and seasonal dynamics of five carabid species (Carabus coriaceus, C. ulrichii, C. violaceus, C. nemoralis and C. scheidleri) in four oak hornbeam forest stands were evaluated using the method of pitfall trapping. The climate water balance values were cumulatively calculated here as cumulative water balance in monthly steps. The cumulative water balance was used to identify the onset and duration of drought. The number of Carabus species individuals was more than three times higher in 2018 than in 2017. Spring activity was influenced by temperature. The extremely warm April in 2018 accelerated spring population dynamics; however, low night temperatures in April in 2017 slowed the spring activity of nocturnal species. Drought negatively influenced population abundance, and the effect of a drought is likely to be expressed with a two-year delay. In our investigation, a drought in 2015 started in May and lasted eight months; however, the drought was not recorded in 2016, and 2016 was evaluated as a humid year. The meteorological conditions in the year influenced seasonal activity patterns and the timings of peaks of abundance for both spring breeding and autumn breeding Carabus species.

Water Balance Measurements for a Single Proton Exchange Membrane Fuel Cell Using a Hot Wire Anemometer

Water balance data for a single proton exchange membrane fuel cell with an active area of 50 cm2 were measured with a hot wire anemometer, placed in the anode outlet stream. The measured hot wire voltage, E, is divided by the calibration signal, E_0, that was taken for a dry hydrogen stream of the same molar flow as the anode outlet at the same temperature. Because water vapor has a much lower thermal conductivity than hydrogen, the recorded hot wire voltage is always lower than the calibration signal, and there is a clear correlation between the relative voltage signal E/E0 and the fuel cell water balance. The relative voltage single can be easily computed at any point in time to thus provide a real-time signal of the fuel cell water balance.This data was for a variety of operating conditions. The results show the same trends that were observed by other researchers who used the water knock-out method, only with higher accuracy. A decrease in the anode inlet relative humidity decreases the water balance value, rd , significantly while the cathode inlet relative humidity only slightly affects the measured water balance. The membrane-electrode-assembly in this work was provided by Hydrogen South Africa – Catalysis (HySA Catalysis). Figure 1

Perencanaan Embung Wae Lerong untuk pemenuhan kebutuhan air irigasi di Daerah Irigasi Wae Lerong Ruteng Provinsi NTT

Embung Wae Lerong terletak di Kota Ruteng Kabupaten Manggarai, memiliki luas tangkapan sebesar 0,606 km2 dan curah hujan tahunan berkisar 2.500-3.000 mm/tahun. Namun pada beberapa lokasi masih mengalami keterbatasan air, sehingga dibutuhkan bangunan penangkap hujan untuk membantu peningkatan potensi pertanian saat musim kemarau. Penelitian ini bertujuan untuk mendesain Embung Wae Lerong sebagai penampung air selama musim hujan agar dapat digunakan dalam pemenuhan kebutuhan air irigasi. Metode yang digunakan adalah metode kuantitatif dengan analisis data secara empiris. Analisis curah hujan digunakan metode Log Pearson III dan analisis debit banjir menggunakan metode Rasional. Perhitungan evapotranspirasi menggunakan metode Penman Modifikasi dan analisis debit andalan menggunakan metode F.J. Mock. Analisis stabilitas lereng menggunakan metode Limit Equilibrium Method dibantu dengan Program GeoStudio Slope/W 2007. Hasil penelitian menunjukkan curah hujan rerata bulanan berkisar 28,87 - 511,99 mm/bulan. Curah hujan periode ulang 50 tahun sebesar 249,28 mm serta debit banjir untuk kala ulang 50 tahun sebesar 12,094 m3/s. Desain tubuh Embung Wae Lerong adalah tinggi 13,5 m, lebar puncak 5 m, panjang embung 81,50 m, kemiringan lereng hulu 1:3, dan kemiringan hilir 1:2,25. Untuk angka keamanan stabilitas tubuh embung nilainya > 1,10 sehingga masih dalam kondisi aman. Kapasitas tampungan Embung Wae Lerong adalah sebesar 86.540,96 m3 dengan luas permukaan genangan sebesar 19.855,69 m2 pada elevasi MAN 1.204,00 m. Ketersediaan debit andalan pada Embung Wae Lerong adalah 0,001 - 0,793 m3/s dan kebutuhan air irigasi untuk Pola Tata Tanam I (Padi-Padi-Palawija) berkisar hingga 0,176 m3/s. Nilai keseimbangan air mengalami defisit pada bulan Mei - September yang berkisar 0,017 - 0,13 m3/s.

Survival of the Qaidam mega-lake system under mid-Pliocene climates and its restoration under future climates

Abstract. The Qaidam Basin in the north of the Tibetan Plateau has undergone drastic environmental changes during the last millions of years. During the Pliocene, the Qaidam Basin contained a freshwater mega-lake system although the surrounding regions showed increasingly arid climates. With the onset of the Pleistocene glaciations, lakes began to shrink and finally disappeared almost completely. Today, hyperarid climate conditions prevail in the low-altitude parts of the Qaidam Basin. The question of how the mega-lake system was able to withstand the regional trend of aridification for millions of years has remained enigmatic so far. This study reveals that the mean annual water balance, i.e. the mean annual change in terrestrial water storage in the Qaidam Basin, is nearly zero under present climate conditions due to positive values of net precipitation in the high mountain ranges and shows positive annual values during warmer, less dry years. This finding provides a physically based explanation for how mid-Pliocene climates could have sustained the mega-lake system and that near-future climates not much different from present conditions could cause water storage in reservoirs, raising lake levels and expanding lake areas, and may even result in restoration of the mega-lake system over geological timescales. The study reveals that a region discussed as being an analogue to Mars due to its hyperarid environments is at a threshold under present climate conditions and may switch from negative values of long-term mean annual water balance that have prevailed during the last 2.6 million years to positive ones in the near future.

The effect of summer drought on the predictability of local extinctions in a butterfly metapopulation.

The ecological impacts of extreme climatic events on population dynamics and community composition are profound and predominantly negative. Using extensive data of an ecological model system, we tested whether predictions from ecological models remain robust when environmental conditions are outside the bounds of observation. We observed a 10-fold demographic decline of the Glanville fritillary butterfly (Melitaea cinxia) metapopulation on the Åland islands, Finland in the summer of 2018 and used climatic and satellite data to demonstrate that this year was an anomaly with low climatic water balance values and low vegetation productivity indices across Åland. Population growth rates were strongly associated with spatiotemporal variation in climatic water balance. Covariates shown previously to affect the extinction probability of local populations in this metapopulation were less informative when populations were exposed to severe drought during the summer months. Our results highlight the unpredictable responses of natural populations to extreme climatic events.

Assessment of applicability of mike 11-nam hydrological module for rainfall runoff modelling in a poorly studied river basin

Introduction. The need to simulate hydrological processes is caused by, among other factors, the complexity of hydrological systems and data insufficiency due to the unavailability or a small number of instrumental observations. Recently, the reanalysis of the climate data supplied by the world’s leading meteorological centres has been used quite successfully in the regions that suffer from the deficit of instrumental information. This paper assesses the applicability of climate reanalysis data to rainfall runoff (“rainfall runoff”) modelling in the poorly studied river basin in Eritrea. Materials and methods. Climate Forecast System Reanalysis (CFSR) data generated by the National Centre for Environmental Prediction (USA) were used. Besides, high-resolution topographic information, generated by the SRTM international research project, was also applied to set the drainage area boundaries and to simulate the river network using such tools as MIKE and GIS. In addition, calibration and validation (evaluation) of the hydrological model (simulation quality) were performed using the Nash-Sutcliffe efficiency criterion, the determination coefficient, and the root mean square error of volumetric and peak flow rates. Results. The results suggest that a considerable overestimation of precipitation in the reanalysis data set, which in turn has a significant effect on other variables such as potential evapotranspiration, leads to a significant discrepancy between water balance values which are simulated and registered by the hydrographs. Conclusions. The applicability of Climate Forecast System Reanalysis (CFSR) data to river flow modelling in arid and semi-arid regions such as Eritrea is questionable. The incompatibility of spatial and temporal variations of initial variables (e.g. precipitation), derived from reanalysis data sets and instrumental observations, is undoubtedly the main reason for errors. Thus, the application of reanalysis data sets and development of hydrological models for the region under study requires further intensive research aimed at identifying most effective mechanisms designated for the harmonization of differences between reanalysis data and field observations. In the course of further research, CFSR information is to be converted into more realistic data; climate reanalysis indicators, provided by other sources and designated for different time scales in the context of the “rainfall runoff” model are to be assessed, and the efficiency of other software systems is to be compared with MIKE 11-NAM.