High Evapotranspiration Rates Research Articles

An in-situ measurement and assessment of evaporative cooling effects of low impact development facilities in a subtropical city

The urban green infrastructure such as the low impact development (LID) facility and traditional garden that are relatively small and characterized by decentralized distributions has been proposed as the most effective way to mitigate urban heat through its evaporative cooling effect. Recently, there have been increasing studies on its temperature reduction and evapotranspiration (ET) rate, but few of them correlate ET with external surface temperature reductions. Therefore, this study investigated the evaporative cooling effects, ET rates, and their relationships by the three-temperature (3T) model and ground-based thermal infrared remote sensing. Results show that the cooling effect of both vegetated LID facilities and traditional gardens is significantly stronger than that of non-vegetated LID facilities. Due to a thinner soil layer and lower water connectivity of LID facilities, their ET rates are significantly reduced in the dry period while the evaporative cooling effect of traditional gardens covered by the same vegetation can maintain high. The dependency of their cooling effect can be largely explained by the ET rates. When ET < 0.6 mm h–1, an increase in ET of 0.1 mm h–1 can enhance the cooling effect by 3.66 °C. When ET exceeds 0.6 mm h–1, the evaporative cooling effect saturates. Vegetation types and soil water conditions are two main factors that govern evaporative cooling effect. Specifically, shrubs with higher ET rates are more efficient in urban heat mitigation than herbs. The responses of the evaporative cooling effect to soil water availability vary among species, which may require species-specific irrigation regime. These results may have implications on the best management practices for urban heat mitigation by the small widely-distributed green spaces.

Factoring labour when comparing in situ rainwater harvesting technologies for semi-arid areas of central Tanzania

ABSTRACT Erratic rainfall, high evapotranspiration rates and droughts are major factors limiting crop production in semi-arid areas. Tied ridges that have crossed ties within the furrow are among the physical soil and water conservation measures. During the 2018/19 and 2019/20 seasons, we examined the efficacy of repaired tied ridges for maize crop (Zea mays) and sorghum (Sorghum bicolor) in Kongwa district of Tanzania as an alternate labour saving strategy for managing climate risks associated with variable rainfall. Treatments consisted of three tillage methods: conventional tillage (CT) which involved the preparation of a flat seedbed using handhoe, annually constructed tied ridges (ATR) and tied ridges that had been constructed during the previous season and had been repaired (residual tied ridges–RTR). Data were collected on labour requirements and crop performance. RTR increased economic returns by 29% and 80% over ATR and CT, respectively. Maize grain yield shows a trend of RTR >ATR>CT with values ranging from 2465 kg ha−1 to 4185 kg ha−1 (P < 0.01). While tillage and/or variety did not influence sorghum grain yield significantly (P > 0.05). The use of RTR is recommended because of low labour requirements and greater economic benefits than CT and ATR under maize cropping systems.

A Historical–Projected Analysis in Land Use/Land Cover in Developing Arid Region Using Spatial Differences and Its Relation to the Climate

Land resources are under relentless pressure from metropolitan regions, pollution, and climate shifts. The urge to monitor Land Use/Land Cover (LULC) and climate changes based on technology and sustainable management are addressed. This study analyzes the historical land cover maps to calculate growth patterns for the years 1985–2022 and uses Logistic Regression (LR) and Artificial Neural Networks (ANN) to project future dynamics forecasts for the years 2030–2040 in the Amman-Zarqa Basin (AZB). The state of the climate and the extreme indices projections of CMIP5 under RCP8.5 are linked to the corrected historical LULC maps and assessed. Given greater dry covering of large surface runoff, little rainfall, and high evapotranspiration rates, the state of the climate across the AZB notably showed instability in key climatic indices and a major exacerbation of warmth and drier soil in the basin. Both climate change and land use are contributing dynamics, but land-use alterations are much more dramatic changes than climate changes. Since the effects of climate alterations are mostly identifiable through land cover forms, land use practices put the phase that may be influenced by climate change. The results revealed that the daily extremes in 1992 are aligned with the corresponding increase of barren lands and diminished the half area of forest, cultivated, rainfed, and pasture lands in 1995. Rainfed regions were converted to agriculture or shrubland with an accuracy of 0.87, and urban encroachment caused the acreage of woodland, cultivated, rainfed, and grazing fields to decrease by almost half. Predicted land cover maps were created using LR in 2030 (Kappa = 0.99) and 2040 (Kappa = 0.90), in contrast to the ANN approach (Kappa = 0.99 for 2030 and 0.90 for 2040). By combining ANN and LR, decreasing bare soil was anticipated between 325 km2 and 344 km2. As a result, 20% of the total area of the major AZB cities’ urban areas will be doubled. More subjective analysis is required to study and predict drought in the future to improve the resilience of various LULC types.

Assessment and mechanism analysis of plant salt tolerance regulates soil moisture dynamics and controls root zone salinity and sodicity in seasonally irrigated agroecosystems

Soil water deficit and saline-alkaline stress impose severe constrains to agriculture and vary across different salt-tolerant crops. Yet, the effects and mechanisms of plant salt tolerance on long-term soil water budget and future root zone (both primary and secondary) salinization and alkalization trends under changing environments in irrigated agroecosystems have not been fully understood, particularly driven by seasonal irrigation practices and stochastic climate conditions. Here, we introduce a robust species-dependent soil water, salinity, and sodicity coupled model that enables explicitly simulation to the feedback between evapotranspiration and salinity being shaped by plant salt tolerance and saturated hydraulic conductivity as affected by salinization and alkalization in seasonally irrigated agroecosystems. Using this model in conjunction with field comprehensive measurements from a typical arid inland river basin in Northwest China, we find that the species-dependent model performed well in simulating the root zone moisture (s), salinity (Cs) and sodicity (Ex) dynamics as driven by seasonal irrigation and random precipitation under different salt-tolerant crops, with average consistency measure (CM) reaching to 0.825 ± 0.017, 0.819 ± 0.027 and 0.728 ± 0.033, respectively. Stochastic simulations indicate that plant salt tolerance plays a predominant role in regulating the feedback of vegetation on soil water budget and root zone salinity and sodicity levels over time in seasonally irrigated agroecosystems. In contrast to salt-sensitive species, salt-tolerant plants seems to exhibit higher efficiency in water extraction from soil, with higher evapotranspiration rates, less frequent leaching events and greater capillary upflow fluxes, thereby lowering soil moisture and boosting salinization and alkalization in the root zone, particularly in arid climates. Sensitivity analysis revealed that plant salt tolerance, together with climatic forcing and anthropogenic perturbations, can significantly modulate the soil water balance and determine the possible trends of root zone salinization and alkalization in future, thus controlling potential risks of soil degradation related to reducing soil hydraulic conductivity Ks(Cs, Ex) in irrigated agroecosystems. Notably, since Ks(Cs, Ex) decreases with plant salt tolerance increases, salt-resilient species have the potential to exacerbate soil degradation. Our results emphasize the importance of comprehensively considering plant salt tolerance for assessing the sustainability of agricultural management practices and environmental protection measures, as well as proposing adaptive strategies under global changes.

A comparative study of fifteen cover crop species for orchard soil management: water uptake, root density traits and soil aggregate stability

Increasing the use of cover crops (CCs) is a necessity in sustainable viticulture, although it might clash with possible excessive competition towards vines. Especially in a climate-change scenario, the latter feature should be minimized while maintaining ecosystem services. Aimed at identifying CCs for vineyard floor management, the trial characterized several species according to their evapotranspiration (ET) rates, root growth patterns, and soil aggregate stability potential. The study was performed in 2020 in Piacenza (Northern Italy) on 15 CC species grown in pots kept outdoor and classified as grasses (GR), legumes (LE) and creeping (CR). Together with bare soil (control), they were arranged in a complete randomized block design. CCs ET was assessed through a gravimetric method, starting before mowing and then repeated 2, 8, 17 and 25 days thereafter. Above-ground dry biomass (ADW), root length density (RLD), root dry weight (RDW) and root diameter class length (DCL) were measured, and mean weight diameter (MWD) was calculated within 0–20 cm depth. Before mowing, ET was the highest in LE (18.6 mm day−1) and the lowest in CR (8.1 mm day−1) the latter being even lower than the control (8.5 mm day−1). The high ET rates shown by LE were mainly related to very fast development after sowing, rather than to a higher transpiration per unit of leaf area. After mowing, the 15 species’ ET reduction (%) plotted vs leaf area index (LAI, m2 m−2) yielded a very close fit (R2 = 0.94), suggesting that (i) a linear decrease in water use is expected anytime starting with an initial LAI of 5–6, (ii) a saturation effect seems to be reached beyond this limit. Selection of cover crop species to be used in the vineyard was mainly based on diurnal and seasonal water use rates as well as dynamic and extent of root growth patterns. Among GR, Festuca ovina stood out as the one with the lowest ET due to its “dwarfing” characteristics, making it suitable for a permanent inter-row covering. CR species confirmed their potential for under-vine grassing, assuring rapid soil coverage, lowest ET rates, and shallow root colonization.

Water Footprint of Constructed Wetlands – Lutopecny Case Study

Constructed wetlands (CWs) are effective low-cost applications of nature-based solutions to the treatment of wastewater from small municipalities and isolated dwellings. One type of evaluation of CWs is focused on the effectiveness of wastewater treatment. Another type of CWs evaluation is focused on water balance because wetland plants are adapted to growth in conditions of unlimited water availability, which is associated with a high rate of evapotranspiration. In this study, the water footprint (WF) was used for joining these two evaluations. The blue WF describes water loss from CWs. The grey WF is an indicator of the effectiveness of CW in terms of pollution reduction. This is the first study of CWs that compares the importance of blue and grey WF under different climatic conditions during the year. Data from different seasons were used to calculate the WF of the CW in a temperate climate zone. During cold days, the grey WF is several times higher than the blue WF. Another situation occurs on hot summer days when the blue WF is higher than the grey WF. On all assessed days, the grey WF reduction was higher than the blue WF reduction; it means that the CW saves more clean water in the recipient (needed to dilute discharged pollution) than losses by evapotranspiration.

Application of GIS technologies in the investigation of soil salinity

Soil salinization is the major problem affecting the productivity of irrigated lands. In Uzbekistan, irrigated area amounts to 4.5 million hectares or about 10% of Uzbekistan’s total area and almost 46.6% of these lands are affected by increasing salinity. The main reason for these conditions of irrigated land is the effect caused by natural factors (primary salinity) - inefficient natural drainage, saline groundwater, high evapotranspiration rates, and high capillary capacity of the soil. Moreover, human-induced processes (so-called “secondary salinity”), which lead to the enrichment of mineralization of groundwater. The objectives of this study iarethe soil salinity monitoring of irrigated lands and the mapping of the temporal and spatial distribution of salt-affected soils for the Arnasay district of Jizzakh province in Uzbekistan to support land management. Field data collected in 2017- 2018 was analyzed and based on the analysis soil map was developed. In the research area, based on these maps changes in soil salinity were identified. The results indicate that inefficient irrigation activities in the region would affect to the enrichment of salts in the top soils and reduce soil productivity. The GIS technologies are efficient tools for monitoring salt-affected lands.

Using machine learning algorithms to predict groundwater levels in Indonesian tropical peatlands

Tropical peatlands play a vital role in the global carbon cycle as large carbon reservoirs and substantial carbon sinks. Indonesia possesses the largest share (65 %) of tropical peat carbon, equal to 57.4 Gt C. Human perturbations such as extensive logging, deforestation and canalization exacerbate water losses, especially during dry seasons, when low precipitation and high evapotranspiration rates combine with the increased drainage to lower groundwater levels. Drying and increasing temperatures of the surface peat exacerbate ignition and wildfire risks within the peat soils. As such, it is critically important to know how groundwater levels in peatlands are changing over space and time. In this study, a multilinear regression model as well as two machine learning algorithms, random forest and extreme gradient boosting, were used to model groundwater level over the study period (2010−12) within a peat dome impacted by drainage canals and multiple wildfires in Central Kalimantan, Indonesia. Although all three models performed well, based on overall fit, spatial modeling of groundwater level results revealed that extreme gradient boosting (R2 = 0.998, RMSE = 0.048 m) outperformed random forest (R2 = 0.997, RMSE = 0.054 m) and multilinear regression (R2 = 0.970, RMSE = 0.221 m) near drainage canals, which are key fire ignition risk locations in the peatlands. Our study also shows that, on average, elevation and precipitation are the most important parameters influencing groundwater level spatiotemporally.

Effect of water quality on the biomass production, nutritional value, and contents of secondary compounds of three genotypes of willow (Salix acmophylla Boiss.) grown for fodder

Shrub willow (Salix spp.) grow naturally in riparian landscapes and combine rapid growth with high rates of evapotranspiration. As willow irrigated with secondary treated wastewater (TWW) can be used as fodder for goats, it could be exploited in otherwise dry areas where such water is available. We examined the effect of irrigating Salix acmophylla Boiss. With secondary treated wastewater (TWW) or municipal freshwater (FW) on growth indices, secondary compounds, and nutritional value of willow fodder over two years grown in 50 L pots in natural soil under ambient conditions. We evaluated ten willow ecotypes belonging to three genotypes (GA, GB, and GC). Biomass production greatly differed among ecotypes. TWW irrigation resulted in a doubling in biomass production, compared with FW. In GA and GC shrubs, the leaf/total weight ratio was higher than in GB. The differences in crude protein (CP) and the in vitro dry matter digestibility (IVDMD) were 2 % and 3 % (in percentage points, on DM basis) higher respectively in plants irrigated with TWW over FW. Salicin and catechin contents were also greater under irrigation with TWW compared with FW. GC produced less salicinoids, in opposite to chlorogenic acid. Overall, genotype did not affect nutritional value but GC shrubs had more resprouting stems and produced more biomass. Our results suggest that willow genotype is important for biomass and secondary compound production and should be taken into account before large-scale planting. Willow crops irrigated with TWW could produce appreciable biomass and quality fodder for livestock under semi-arid and arid conditions.

Grassland afforestation

The establishment of tree plantations on native grasslands is expanding in Argentina and Uruguay, prometed by public incentives and, likely, by an emerging market of carbon sequestration. We assessed how this transformation affects the production of ecosystem goods and services, synthesizing preexisting and original information on their influence on biomass production, water dynamics, and nutrient cycling. Field and satellite measurements show that, compared to grasslands, tree plantations in Uruguay, Entre Ríos, and Corrientes had higher primary productivity. This productivity increase was accompanied by higher evapotranspiration rates and a lower water yield, responsible of halving stream flow in afforested watersheds in Córdoba and Uruguay, in agreement with observations on 26 afforested grasslands around the world. In Buenos Aires, where phreatic water is close to the surface, trees used groundwater increasing the salinity of deep soil and the water table. Most of the tree plantations in the region acidified soils and in some cases stream water, mainly as a result of their high calcium consumption. It is urgent to generate information about other impacts of tree plantations such as changes in fire dynamics or invasive species. An integrative understanding of the influence of tree plantations on the production of goods and services will help to development new forestry systems and policies that are more sustainable and useful for society.

Spatiotemporal Analysis of Urban Heat Islands in Relation to Urban Development, in the Vicinity of the Atacama Desert

Near the Atacama Desert, Tacna city in Peru is among the largest arid cities with constant urban development, thus understanding of the urban surface thermal pattern is needed. We propose a comprehensive study of the urban heat island phenomenon, with the objective of (1) determining the spatial and temporal variations of the urban heat islands (UHIs), in the period 1985 to 2020; (2) analyzing the relationship between the UHI and influencing factors such as vegetation, urban area, and population, using indices calculated with satellite images. The Google Earth Engine repository was used to evaluate the corrected images from the years 1985 to 2020. The coincidence between the normalized difference vegetation index (NDVI) and normalized difference built-up index (NDBI) was good, negative between NDVI and the land surface temperature (LST), attributable to dense vegetation, and negative and very high (−0.81) between NDBI and NDVI, as massive urbanization leads to the reduction in the vegetal surface. The NDBI has a high impact on the LST; a coefficient of connections is recorded as 0.46. Tacna is a very arid region, and an increase in the time of the LST occurred with the increase in industrialization and urbanization. The land use/cover change (LUCC) evidences change in the climate in the city of Tacna; temperatures of 24.2 °C to 44.2 °C are observed in the built-up areas. In vegetated areas, the temperature remains below 24 °C, which is associated with a high rate of potential evapotranspiration. Thus, this study shows that variations in urban form and growth have produced the development of intraurban surface thermal patterns.

Soil Moisture Influence on the FTIR Spectrum of Salt-Affected Soils

Soil salinity has a major impact on agricultural production. In a changing climate with rising sea-levels, low-lying coastal areas are increasingly inundated whereby saltwater gradually contaminates the soil. Drought prone areas may suffer from salinity due to high evapotranspiration rates in combination with the use of saline irrigation water. Salinity is difficult to monitor because soil moisture affects the soil’s spectral signature. We conducted Fourier-transform infrared spectroscopy on alluvial and sandy soil samples in the coastal estuary of the Red River Delta. The soils are contaminated with NaCl, Na2CO3 and Na2SO4 salts. In an experiment of salt contamination, we established that three ranges of the spectrum were strongly influenced by both salt and moisture content in the soil, at wavenumbers 3200–3400 cm−1 (2.9–3.1 µm); 1600–1700 cm−1 (5.9–6.3 µm); 900–1100 cm−1 (9.1–11.1 µm). The Na2CO3 contaminated soil and the spectral value had a linear relationship between wavelengths 6.9 and 7.4 µm. At wavelength 6.99 µm, there was no relationship between absorbance and soil moisture, but the absorbance was proportional to the salt content (R2 = 0.85; RMSE = 0.68 g) and electrical conductivity (R2 = 0.50; RMSE = 3.8 dS/m). The relationship between soil moisture and spectral absorbance value was high at wavelengths below 6.7 µm, resulting in a quadratic relation between soil moisture and absorbance at wavelength 6.13 µm (R2 = 0.80; RMSE = 5.2%). The spectral signatures and equations might be useful for mapping salt-affected soils, particularly in difficult to access locations. Technological advances in thermal satellite sensors may offer possibilities for monitoring soil salinity.

English

Green water is the water that is used in biomass production, and if well conserved this water can boost agricultural production. Drylands experience erratic rainfalls, poor soils and high rates of evapotranspiration. This situation has been made worse by climate variability as drylands are very sensitive to climate change due to their delicate nature. The effect of climate change in ASALs has resulted in poor agricultural production hence loss of livelihoods. Good management of green water during the rainy season can greatly increase agricultural production thus improving livelihoods. This&nbsp;&nbsp; research paper investigated the biophysical and socioeconomic factors that influence green water management with a focus on Kyawango sub-catchment. Data collection was collected through focus group discussions, key informant interviews, observation study, and household questionnaires. The household survey was carried out in 147 households which was the target population for the research location. The results revealed that management of the green water is determined by biophysical factors such as rainfall, soil type and socioeconomic factors such as demographic and, governance. The researcher further suggests strategies of encouraging communities to conserve green water for increased agricultural production and improved livelihoods. Key words: Climate variability, ecosystem services on farm, diversification.

Long-term drought adaptation of unirrigated grapevines (Vitis vinifera L.)

Resilience to drought stress is an important crop selection and breeding target particularly under an environment of increasing freshwater scarcities resulting from higher evapotranspiration rates and reduced precipitation. Identifying new genetic material and clones with superior drought tolerance would increase available genetic resources and germplasm for both grapevine breeders and propagators, providing genetic material that has greater water use efficiency thereby reducing reliance on supplemental irrigation. Towards this goal, we explored the long-term drought adaptation of field-grown, unirrigated (or dry-grown) and own-rooted grapevines of pre-clonal origin from shallow (SR) and deep (DR) soils representing low and high soil water availability, respectively, in a South Australian vineyard. Despite lower soil moisture available to SR vines, both deep and shallow-rooted vines had similar vine water status, based on measurements of midday stem water potential ({Psi }_{s}), and leaf net photosynthesis (An). Due to the lower stomatal conductance (gs), SR had higher intrinsic water use efficiency (WUEi) than DR, however the carbon isotope ratio ({delta }^{13}C) of the fruit at harvest was similar between the two groups. Our observations suggest a degree of drought adaptation in the SR vines resulting from multi-decadal cyclical droughts. Overall, we demonstrate that pre-clonal Cabernet Sauvignon grapevines dry-grown in shallow soils have an enhanced resilience to drought compared to dry-grown vines in deep soils. This study has implications for selection of crop genetic material in a changing climate.

Stable isotope variability of precipitation and cave drip-water at Jumandy cave, western Amazon River basin (Ecuador)

Monitoring studies are necessary to better understand the hydrological processes affecting the isotopic signature of cave waters, which are ultimately recorded in speleothems that are used as paleoclimate archives. This research examines changes in the isotopic composition (δ18O and δ2H) of precipitation as it infiltrates through the epikarst and into the Jumandy cave, located in the western Amazon Basin (Ecuador). Meteorological and hydrological parameters were monitored outside and inside the cave, and isotope analyses were carried out in waters from rainfall, an underground river, and drip-water at two sampling sites in the cave between April 2019 and February 2020. At monthly timescale, the rainfall weighted isotopic composition monitored at our stations was strongly correlated with the mean precipitation amount. However, when considered at weekly time-steps, the correlation is only moderate. This implies that the variation of the isotopic composition in the study area cannot be interpreted exclusively as an amount effect. Isotopic values and back-trajectory modeling show that the isotopic signature was affected by the moisture source effect associated with upstream rainout. The moisture flux is dominantly from an east to northeast direction and moisture mainly originates over the Atlantic Ocean, passing through the Amazon Basin. A significant fraction of moisture is associated with local sources within the Amazon Basin. This aspect is confirmed by d-excess values of rainfall and the Local Meteoric Water Lines (LMWLs) that indicate an influence of the high evapotranspiration rate of the Amazon region on the isotopic composition of local rainfall. The infiltrated water resides for about three weeks in the epikarst and then precipitates forming speleothems (residence time). However, this short residence time needs to be confirmed with a longer monitoring period. Despite the different magnitudes of the dripping rates, the isotopic values at the two monitored sites are similar. This suggests that the dripping discharge rate is affected by the karst structure, but the isotopic signature reflects the mixing of individual rainfall events above the cave. Therefore, ẟ18O in speleothems from these caves is mainly recording short-term precipitation changes linked to regional and large-scale atmospheric circulation.

A UAV-derived thermal infrared remote sensing three-temperature model and estimation of various vegetation evapotranspiration in urban micro-environments

The large-scale and single-point observations on urban vegetation easily cause the difficulty to quantitatively study the evapotranspiration of vegetation in urban micro-environments. In this content, the three-temperature (3T) model by combining the UAV-derived thermal infrared data was applied to estimate the evapotranspiration of different urban vegetation types at the microscale in Nanjing city, China accurately. The diurnal variation characteristics of the evapotranspiration rates of the different vegetation types such as arbors, shrubs and grasslands in different seasons were quantitatively analysed. The results showed that the estimated vegetation evapotranspiration rate was between 0–1.4 mm/h. The highest evapotranspiration rate among the different vegetation types was that of arbors, followed by shrubs and grasslands. The evapotranspiration rate on the sunny side was significantly higher than that on the shady side. There were obvious seasonal differences in vegetation evapotranspiration, which gradually decreased from spring to winter. The transpiration transfer coefficients of vegetation in summer and winter were significantly higher than those in other seasons, which indicated that the effects of water deficits or environmental stress were the largest at these times. The UAV-derived thermal infrared remote sensing three-temperature (3T) can simplify the complexity of the calculations and ensure the accuracy of the estimation results, which may provide the high spatio-temporal resolution urban vegetation evapotranspiration.

THE SENSITIVITY OF EVAPOTRANSPIRATION FOR LAND USES AND TOPOGRAPHY IN AREA OF CERRADO BIOME – BRAZIL

Evapotranspiration (ET) is a crucial element in the spatiotemporal dynamics of moisture, energy, and heat, and is related to climatic, pedogeomorphological, and phytophysiognomic aspects of the landscape. Therefore, estimating ET requires dynamic and integrated temporal analysis with biophysical landscape factors. The study aimed to analyze the behavior of ET through the analysis of land use and land cover and topographic in time series. The Simple Algorithm for Evapotranspiration Recovery (SAFER) model was used to obtain the variable ET in the periods of 01/21, 02/22, 05/13 and 06/30/2019 (variables). A database of explanatory covariates was constructed, including land use and land cover, satellite image data (Landsat-8) and digital elevation model (SRTM). The values of variables and covariates were extracted into a grid of points and separated for three altimetric conditions, and the linear Gaussian Models (GLM) were applied to the point data. The most explanatory spectral covariates for the ET variation were Albedo and Surface Temperature. And the covariates related to topography were Digital Elevation Model and Topographic Moisture Index. In general, the wet period presents a higher ET rate (2.06 mm d-¹). Forests generated the highest ET regardless of period (1.62 mm d-¹ to 4.03 mm d-¹). Elevated topography also influences the increase in ET in relation to the same lower altimetry classes (A2 and A3). This influence is associated with the altitude dynamics and intrinsic elements of the region, such as the marshy environment in the A3 region, where the highest ET values occurred. This work stands out from its peers for addressing the influence of landscape aspects on the knowledge of evapotranspiration variation, a vanguard theme in the scope of spatial analysis.

Using Remote Sensing to Estimate Scales of Spatial Heterogeneity to Analyze Evapotranspiration Modeling in a Natural Ecosystem

Understanding the spatial variability in highly heterogeneous natural environments such as savannas and river corridors is an important issue in characterizing and modeling energy fluxes, particularly for evapotranspiration (ET) estimates. Currently, remote-sensing-based surface energy balance (SEB) models are applied widely and routinely in agricultural settings to obtain ET information on an operational basis for use in water resources management. However, the application of these models in natural environments is challenging due to spatial heterogeneity in vegetation cover and complexity in the number of vegetation species existing within a biome. In this research effort, small unmanned aerial systems (sUAS) data were used to study the influence of land surface spatial heterogeneity on the modeling of ET using the Two-Source Energy Balance (TSEB) model. The study area is the San Rafael River corridor in Utah, which is a part of the Upper Colorado River Basin that is characterized by arid conditions and variations in soil moisture status and the type and height of vegetation. First, a spatial variability analysis was performed using a discrete wavelet transform (DWT) to identify a representative spatial resolution/model grid size for adequately solving energy balance components to derive ET. The results indicated a maximum wavelet energy between 6.4 m and 12.8 m for the river corridor area, while the non-river corridor area, which is characterized by different surface types and random vegetation, does not show a peak value. Next, to evaluate the effect of spatial resolution on latent heat flux (LE) estimation using the TSEB model, spatial scales of 6 m and 15 m instead of 6.4 m and 12.8 m, respectively, were used to simplify the derivation of model inputs. The results indicated small differences in the LE values between 6 m and 15 m resolutions, with a slight decrease in detail at 15 m due to losses in spatial variability. Lastly, the instantaneous (hourly) LE was extrapolated/upscaled to daily ET values using the incoming solar radiation (Rs) method. The results indicated that willow and cottonwood have the highest ET rates, followed by grass/shrubs and treated tamarisk. Although most of the treated tamarisk vegetation is in dead/dry condition, the green vegetation growing underneath resulted in a magnitude value of ET.

A Review on Reclamation and Management Practices of Wind Erosion and Salt – Affected Soils of Sudan

Wind erosion and salt–affected soils are predominant desertification processes in Sudan, particularly in the northern part, and have adverse impacts on agricultural lands in the arid and semi-arid lands characterized by erratic rainfall, high temperature, high wind velocity and consequent high rates of evapotranspiration. The main objective of this paper is to present research review on combating, control, reclamation and management practices in areas affected by wind erosion and salt–affected soils. The study showed that the principal measures for controlling wind erosion depends on minimizing certain conditions that can be accelerated wind erosivity (winds ≥ 5.4 m/sec) and vice versa maximizing soil erodibility by creation a suitable condition for generate of non–erodible soil particles (NEP) versus soil surface detachment and transport by wind. Wind erosion research requires high financial support, thus this cost should be borne by government. The strategy of management practices of saltaffected soils aimed to sustain a level of salinity tolerable to the cultivated crops through good manages to water and crop. Assessment and mapping of wind erosion and salt-affected soils is urgent need to determine the inherent risk in the affected areas included in investment map of agricultural land capabilities of the country. Encourage studies on stabilizing soil particles by various natural or synthetic cementing and flocculation materials which are friendly to soil environment to increase NEP on the soil surface. Practical programs on reclamation of salt–affected soils should be included in national development programs and national strategy for scientific research in the State.

Hydrometeorological Modeling of Limpopo River Basin in Mozambique with TOPMODEL and Remote Sensing

The Limpopo River basin (LRB) is known for its vulnerability to floods, high rates of evapotranspiration, and droughts that cause significant losses to the local community. The present study aimed to perform simulations of flood events occurring in two Mozambican sub-basins of LRB, namely Chókwè and Xai-Xai from 2000 to 2015 with TOPography-based hydrological MODEL (TOPMODEL) and satellite remote sensing data. As input in TOPMODEL, data from two high-resolution global satellite-based precipitation products: Climate Prediction Center MORPHing technique (CMORPH) and Integrated Multi-Satellite Retrievals for the Global Precipitation Mission (GPM) algorithm (IMERG), 8-day MOD16 evapotranspiration product and surface runoff data estimated by Global Land Data Assimilation System (GLDAS) were used. The sensitivity tests of TOPMODEL parameters were applied using the Monte Carlo simulation. Calibration and validation of the model were performed by the Shuffled Complex Evolution (SCE-UA) method and were evaluated with the Kling-Gupta Efficiency (KGE) index. The results indicated that simulations with the GPM-IMERG (KGE: 0.59 and 0.65) tended to underestimate the stream flows, while with the CMORPH product the performance was much better (KGE: 0.66 and 0.77) in both sub-basins. Thus, TOPMODEL can help to develop flood monitoring systems from satellite remotely sensed data in similar regions of Mozambique.