Runoff Modeling

Many rivers in Nepal are either ungauged or poorly gauged due to extreme complex terrains, monsoon climate and lack of technical and financial supports. In this context the role of hydrological model is extremely useful. In practical applications, hydrological models are relatively simple to implement and reasonably accurate. The present study concerns about simulating the flow of the Marshyangdi river basin and validate with the gauge station within the studied basin area. Furthermore, estimation and analysis of discharges for each subbasins of Marshyangdi river basin has be performed in this study. The HEC-HMS 4.3 hydrologic model (Developed by US Hydrologic Engineering Center was used to calibrate (from 2003-2007) and validate (from 2008-2012) the Marshyangdi river basin. The main data required as input includes rainfall, DEM (digital elevation model) soil, land use and metrological for model. After having data, HEC-HMS model are operated. The main output from model is discharge ...

The Soil and water assessment tool (SWAT) model is a flexible, physically distributed model was developed as a river basin scale to quantify and predict runoff and transportation from watersheds and river basins. The semi-automated Sequential Uncertainty Fitting (SUFI2) calibration process built in SWAT calibration and uncertainty program (SWAT-CUP) were used to calibrate the model parameters using time series of flow and sediment load data of 1994 to 2002 and validated with the observed data from years 2002 to 2007. The performance of the model was evaluated using statistical and graphical methods to assess the capability of the model in simulating the runoff and sediment yield for the study area.  The result showed relatively good fitness between measured and simulated discharge and sediment. The Nash Sutcliffe efficiency and R2 were nearly 70% for discharge and 76% for sediment load. Overall, simulation of runoff and sediment is satisfactory by using the SWAT model.

Keywords: Runoff; Sediment Yield; Calibration; Validation; SWAT-CUP; SUFI2

Land surface processes play an important role in the West African monsoon variability. In addition, the evolution of hydrological systems in this region, and particularly the increase of surface water and runoff coefficients observed since the 1950s, has had a strong impact on water resources and on the occurrence of floods events. This study addresses results from phase 2 of the African Monsoon Multidisciplinary Analysis (AMMA) Land Surface Model Intercomparison Project (ALMIP2), carried out to evaluate the capability of different state-of-the-art land surface models to reproduce surface processes at the mesoscale. Evaluation of runoff and water fluxes over the Mali site is carried out through comparison with runoff estimations over endorheic watersheds as well as evapotranspiration (ET) measurements. Three remote-sensing-based ET products [ALEXI, MODIS, and Global Land Evaporation Amsterdam Model (GLEAM)] are also analyzed. It is found that, over deep sandy soils, surface runoff is generally overestimated, but the ALMIP2 multimodel mean reproduces in situ measurements of ET and water stress events rather well. However, ALMIP2 models are generally unable to distinguish among the two contrasted hydrological systems typical of the study area. Employing as input a soil map that explicitly represents shallow soils improves the representation of water fluxes for the models that can account for their representation. Shallow soils are shown to be also quite challenging for remote-sensing-based ET products, even if their effect on evaporative loss was captured by the diagnostic thermal-based ALEXI. A better representation of these soils, in soil databases, model parameterizations, and remote sensing algorithms, is fundamental to improve the estimation of water fluxes in this part of the Sahel.

Aam Talaab also known as Maavina Kere or mango beach is one of the major attractions of Raichur. It is located between Latitude 16º10′49.5′′ N to 16º11′27.8′′ N Latitude and 77º20′36′′ E to 77º23′26′′ E Longitude and an area of 4.77 km 2 , having maximum length of 3.98 km. The maximum and minimum elevation of the basin is 491 m and 404 m above MSL, respectively. The values of Stream frequency is 6.50, Form factor 0.30, Shape factor 3.32, Elongation Ratio 0.62, Circularity Ratio 0.39, Drainage density 2.66, Length of overland flow 0.19. The study of hypsometric properties of Aam Talab watershed using hypsometric integral (HI) and hypsometric curve retrieved in that, HI value is 0.52 and hence watershed falls under the Mature Stage. Rainfall was estimated by considering precipitation data from 1998 to 2016 it was found that maximum percentage of runoff took place in 2009 and minimum in the year 2012.

Use of rainfall anomaly based Standardized Precipitation Index (SPI) and satellite-derived Vegetation Condition Index (VCI) are becoming common to assess the impacts of drought on crops. This study analyzed spatio-temporal intra-seasonal and inter-seasonal relationships for 24 years between rainfall and NDVI and between SPI and VCI to understand crop response to water availability in the Rajasthan State, India. To separate the effect of weather and technology on crop growth over time, a modification in VCI was proposed and called "Trend Adjusted VCI" (VCITadj). The VCITadj was computed for early, mid, late and whole crop seasons by deriving pixel wise crop phenology metrics from NDVI profile. Significant linear relationships were found between NDVI and rainfall but phase of crop season affected the strength of this relationship. The SPI and VCITadj were linearly related in all the four seasons, the strength of relationship improved with the progress of crop season and these relationships were stronger than between rainfall and NDVI. These relationships broke down in irrigated croplands. As a result, the anomaly indices of SPI and VCITadj and their intra-seasonal relationships can be used to study the response of crops to water availability for early detection and better prognosis of agricultural drought.

Many hydrologic applications require reliable estimates of runoff in river basins to face the widespread lack of data, both in time and in space. A regional method for the reconstruction of monthly runoff series is here developed and applied to Sicily (Italy). A simple modeling structure is adopted, consisting of a regression-based rainfall–runoff model with four model parameters, calibrated through a two-step procedure. Monthly runoff estimates are based on precipitation, temperature, and exploiting the autocorrelation with runoff at the previous month. Model parameters are assessed by specific regional equations as a function of easily measurable physical and climate basin descriptors. The first calibration step is aimed at the identification of a set of parameters optimizing model performances at the level of single basin. Such " optimal " sets are used at the second step, part of a regional regression analysis, to establish the regional equations for model parameters assessment as a function of basin attributes. All the gauged watersheds across the region have been analyzed, selecting 53 basins for model calibration and using the other six basins exclusively for validation. Performances, quantitatively evaluated by different statistical indexes, demonstrate relevant model ability in reproducing the observed hydrological time-series at both the monthly and coarser time resolutions. The methodology, which is easily transferable to other arid and semi-arid areas, provides a reliable tool for filling/reconstructing runoff time series at any gauged or ungauged basin of a region.

Rapid urbanization in the recent decades has quickly fuelled up the process of global warming. Many mitigation measures have been formulated and
implemented in order to tackle the effect of global warming. Green roofs (roof with vegetated cover) have been proposed and implemented by various
countries as one of the new environmentally friendly innovation. This paper evaluates the qualitative and quantitative performances of an extensive
green roof system under tropical climate. Simulations showed that the peak discharge of stormwater run-off was reduced up to 26% in relation to concrete tile roof. Its reduction ability was decreased for storms with intense rainfall. Increment of pH was observed for the green roof run-off, and the runoff quality ranged between class I and II under Malaysia National Water Quality Index (WQI). High concentrations of phosphate were observed in the
run-off samples, which showed that substrates (fertilized planting soil) might be the potential contributor. Findings indicated that there was a reduction
up to around 5% for indoor temperature of the building after installation of the extensive green roof system.

The undisputable significance of water resources necessitates solving problems related to the amount and distribution of water. However, existing methods and the outcomes obtained via these methods are continuously criticized and do not meet the expectations in terms of reliability.  On the other hand, increasing need to plan water resources and lack of alternative methods to determine the water potential in areas where flow measurement does not exist make it impossible to evade dependency on these methods. With this purpose  generated flexible, comprehensive and reliable runoff distribution map was formed on the basis of weighted overlay in parallel to impact degrees of effective parameters. The calibration of the obtained map was done on the basis of pixels based on both theoretical and empirical data. As a result of the analyses, it was seen that an accurate runoff distribution model that fully reflects the characteristics of the field can only be developed by calibrating it based on the real flow data obtained from remote sub-basins that are free from external interventions. It would be impossible to free the theoretical approaches from errors since these approaches are related to amount of water which has an active nature and interacts with factors that are beyond measure. As a result of implementing the method on Ergene River Basin, the sample basin, a surface runoff volume of an average183,45mm/year/m², i.e. a total of  2100000000m³/year ±2% was obtained for the basin and this result has at least 27% difference from the results obtained with existing methods.

Developing nations are imposing the increasing impacts on their bio-resources due in part to their rising population, need to high economic growth and the incorporation of non-native technologies. Usually, watersheds are the major units, which are influenced leading to un-sustainability, specifically from the view point of water resources and hydrologic systems. Relying on a linear causal thinking, most of the hydrologic models fail to incorporate socioeconomic attributes of a watershed with its hydrologic and environmental ones. Based on a systems thinking philosophy, this paper aims to adopt an object-oriented approach based on the concepts of System Dynamics (SD) to analyze the dynamics in a hydrologic system in a watershed scale. This research focuses on a storm event and investigates the interaction between key elements of rainfall-runoff phenomenon. The paper adopts the concepts of SD such as stocks and flows to define objects in an OO-SD model. The results of the study show that this approach is capable of simulating rainfall runoff process and estimate the value of peak flow exactly. Also the model was compared with HEC-HMS and results showed that using Snyder method for HEC-HMS the exact value of peak flow is obtained for both events. The simplicity of the adopted methodology in this study doesn't limit the accuracy of runoff peak estimation.

India is a country of villages with 68.84% of the total population living in rural areas. The villagers are lagging in their developments due to the scarcity of water. Hence in this study, it was decided to find out the technique of water conservation which will sustain in rural areas and to compile the results by applying the model which will work for this. Considering the topographical features of a small plot of area two hectares of Kaneri watershed situated in Kolhapur District, Maharashtra, the structures for water conservation had been implemented in it in June 2011. The structures included gully plugs on existing water stream followed by the farm pond at its end along with farm terraces and continuous contour trenches surrounding the water stream. The practical evidence proved the positive impact of water conservation structures on water conservation and groundwater recharge. For assessing this impact technically for ungauged Kaneri watershed, SWAT (Soil and Water Assessment Tool) Model was used in the study and both the results were compiled. From the model results, the sediment yield and water yield showed expected impact on the watershed. Thus, the SWAT model proved to be an effective tool in assessing the impact of changes in land management on runoff and sediment yield.

Gully erosion signifies instability in the landscape, and it is regarded as a threshold phenomenon under certain conditions in the landscape, relating to flow erosivity and surface resistance. The main cause of gully formation is too much water at a certain location of slope-a threshold condition that may be brought about by external factors or internal factors. Intense rainfall is the primary trigger, but the local conditions such as slope morphome-try, land-use and soil characteristics control the triggering of gully erosion. The catchment size above a stream or gully head and the land-use characteristics determine the volume of overland flow but it is different from the concentrated-flow area by its position on the slope. In the present study, the models of geomorphic threshold and the M-D Envelope have emphasized on the role of overland flow (as surface runoff) for initiation of gullies in the laterite slope of Dwarka-Brahmani Interfluve, West Bengal (Neogene-Early Pleistocene lateritic terrain located in between the Rajmahal basalt traps and Bengal basin). The upstream laterite slopes above gully heads are negatively correlated (r ¼ 0.55) with upstream drainage areas which are used as surrogate for the volume of runoff yield in the gullies of the study area. The calculated empirical trend line (S ¼ 17.419 A 0.2517 , with R 2 of 0.52) represents an approximation to critical slope-area threshold relationship for gully incision in this region. Then, the Soil Conservation Service-Curve Number (SCS-CN; now called the National Resource Conservation Service, NRCS-CN) method is used for quick and accurate estimation of surface runoff in any storm event in the ungauged watersheds of gullies. Experimenting in three sample watersheds of gullies, it is found that on the basis of rainfall range of 42-137.2 mm the gullies can yield runoff of 40.02-118.0 mm in excess moisture condition of monsoon. The differences of runoff in the catchments for the same rainfall event are the direct effects of land use-land cover derived from CN values. In the gully catchments, the estimated runoff is increased above 22% from Antecedent Moisture Condition (AMC) II to AMC III and in most gullies it ranges from 22.33% to 85.73%. It is understood that if the rainfall amount is increased day by day, the runoff coefficient (R c) is also increased consecutively and it will be high runoff event which is the sign of high vulnerability of flow erosion on the bare laterite slope. The SCS-CN analyses reflect that in prolong rainfall event of tropical depression more than 86% of rainfall can be transformed into direct runoff, as R c is reaching up to 0.86. Alongside, it gives more hydraulic energy to gully initiation and gully head migration in AMC III condition. Based on the daily rainfall-runoff modelling and annual potential erosion rate, the estimated sediment yield varies from 5.0 to 13.45 t ha 1 in the gullies. It is learnt that in prolong rainstorm event or in cyclonic rainfall, with increase of rainfall and moisture content of surface, the transport of eroded materials is increased and substantially, the sediment yield of gully catchment is also escalated.

Soil erosion by water is recognised as a worldwide land degradation issue, particularly in arid and semi-arid regions. The aim of this study is to apply the powerful capabilities of advanced remote sensing and geographic information system techniques to identify the areas at risk to water erosion. This study presents the assessment of water erosion in mountainous areas (eastern Aures, Algeria) based on three main factors: the friability of the bedrock, degree of slope and density of vegetation cover. Alsat1 image was used to produce land use and vegetation (NDVI) maps. Digital elevation model was used in constructing the slope gradient map. The erosion risk map was obtained by the combination of indices assigned to thematic layers following multicriteria decision rules. Water erosion was generally not concerning in the eastern Aures (slight risk = 33 %, moderate risk = 44 % of the area). This simple–qualitative approach gave good results for assessing soil erosion equally to quantitative methods since 89.55 % of field verifications were accurate. The non-alarming state and the low rate of severe and extremely severe risk to erosion are due to (1) the low steep slopes, (2) the good quality of vegetation (forests with thick undergrowth), and which are occurring on (3) resistant materials of the substratum, and (4) the low human pressure. Results of this study, which may be conducted with reasonable costs and accuracy over large areas, are of significant help in prioritising areas in decision making and sustainable planning.

" Models and observations show that the Arctic is experiencing the most rapid changes in global near-surface air temperature. We developed novel EASE-grid Level 3 (L3) land surface temperature (LST) products from Level 2 (L2) AATSR and MODIS data to provide weekly, monthly and annual LST means over the pan-Arctic region at various grid resolutions (1–25 km) for the past decade (2000–2010). In this paper, we provide: (1) a review of previous validation of MODIS/AATSR L2; (2) a description of the
processing chain of L3 products; (3) an assessment of the 25 km products uncertainty, and; (4) a quantification of the bias introduced by over-representing clear-sky days in MODIS L3 products. In addition, we generated uncertainty maps by comparing L3 products with LST from passive microwave sensors (AMSR-E and SSM/I) and the North American Regional Reanalysis (NARR). Results show a close correspondence between MODIS and AATSR monthly products with a mean-difference (MD) of −1.1 K. Comparing L3 products with NARR indicates a close agreement in summer and a systematic bias in winter, which is entirely negative with respect to MODIS L3 (MD: −3.6, Min: −6.8, Max:
−1 K). Comparing monthly averaged MODIS L3 to NARR clear-sky to quantify over-representing clear-sky days indicates a decrease of winter and an increase of summer difference compared to NARR all-sky. Finally, we provide suggestions to improve LST retrieval over Arctic regions."

Hydrologic soil groups (HSGs) are a fundamental component of the USDA curve-number (CN) method for estimation of rainfall runoff; yet these data are not readily available in a format or spatial-resolution suitable for regional-and global-scale modeling applications. We developed a globally consistent, gridded dataset defining HSGs from soil texture, bedrock depth, and groundwater. The resulting data product—HYSOGs250m—represents runoff potential at 250 m spatial resolution. Our analysis indicates that the global distribution of soil is dominated by moderately high runoff potential, followed by moderately low, high, and low runoff potential. Low runoff potential, sandy soils are found primarily in parts of the Sahara and Arabian Deserts. High runoff potential soils occur predominantly within tropical and subtropical regions. No clear pattern could be discerned for moderately low runoff potential soils, as they occur in arid and humid environments and at both high and low elevations. Potential applications of this data include CN-based runoff modeling, flood risk assessment, and as a covariate for biogeographical analysis of vegetation distributions.

We investigated changes in snow cover depth in eastern Europe over a period of about 100 yr, analyzing data for 5 stations located on the territory of the former Soviet Union. First we determined the basic characteristics of snow cover occurrence at each station: mean and extreme values of snow cover depth, standard deviation and variability index. Then, trends of changes in the mean monthly snow cover depth were analysed and turning points were identified using a Mann-Kendall test. Snow cover depth has decreased significantly at the 3 easternmost stations (Orenburg, Kirov, Gorkij), but at Kirov snow cover depth has increased again since 1950. At Vilnjus snow cover depth has decreased rapidly since the early 1980s.

Accurate and consistent annual runoff prediction in a region is a hot topic in management, optimization, and monitoring of water resources. A novel prediction model (ESMD-SE-WPD-LSTM) is presented in this study. Firstly, extreme-point symmetric mode decomposition (ESMD) is used to produce several intrinsic mode functions (IMF) and a residual (Res) by decomposing the original runoff series. Secondly, sample entropy (SE) method is employed to measure the complexity of each IMF. Thirdly, wavelet packet decomposition (WPD) is adopted to further decompose the IMF with the maximum SE into several appropriate components. Then long short-term memory (LSTM) model, a deep learning algorithm based recurrent approach, is employed to predict all components. Finally, forecasting results of all components are aggregated to generate the final prediction. The proposed model, which is applied to seven annual series from different areas in China, is evaluated based on four evaluation indexes (R, MAE, MAPE and RMSE). Results indicate that ESMD-SE-WPD-LSTM outperforms other benchmark models in terms of four evaluation indexes. Hence the proposed model can provide higher accuracy and consistency for annual runoff prediction, rendering it an efficient instrument for scientific management and planning of water resources.

In this study we estimated ETCCDI and frequency based precipitation using observed precipitation and precipitation from Representative Concentration Pathway(RCP) scenarios for 58 weather stations which have the recorded data more than 30 years.  We tried to eliminate the bias by Quantile Mapping and tested for outliers of simulated data under climate change scenario. Then we estimated ETCCDI related to precipitation and frequency based precipitation for the future. In addition to this study examined the changes of frequency based precipitation for the future target periods. According to the result, dry days will be increased in Korean Peninsula in the 2090s. Also it showed that the number of heavy precipitation day more than 80mm/day tends to be increased in 3∼7% in the future. The precipitation of 24-hour duration under climate change will be increased by 17.7% for 80-year frequency, 18.2% for 100-year frequency and 19.6% for 200-year frequency in 2090s. In the 21st century, the damage caused by natural disasters is expected to be increased due to  increase of precipitation and the change of runoff characteristics under climate change. Therefore, the proposed ETCCDI and precipitation frequency under climate change are expected to be used for the future natural disaster plan.

"Mass-balance and dynamic behaviour of Chhota Shigri glacier, western Himalaya, India, has been investigated between 2002 and 2010 and compared to data collected in 1987–89. During the period 2002–10, the glacier experienced a negative glacier-wide mass balance of –0.670.40m w.e. a–1. Between 2003 and 2010, elevation and ice-flow velocities slowly decreased in the ablation area, leading to a 24–37% reduction in ice fluxes, an expected response of the glacier dynamics to its
recent negative mass balances. The reduced ice fluxes are still far larger than the balance fluxes calculated from the 2002–10 average surface mass balances. Therefore, further slowdown, thinning and terminus retreat of Chhota Shigri glacier are expected over the next few years. Conversely, the 2003/04
ice fluxes are in good agreement with ice fluxes calculated assuming that the glacier-wide mass balance is zero. Given the limited velocity change between 1987–89 and 2003/04 and the small terminus change between 1988 and 2010, we suggest that the glacier has experienced a period of near-zero or slightly positive mass balance in the 1990s, before shifting to a strong imbalance in the 21st century. This result challenges the generally accepted idea that glaciers in the Western Himalaya have been shrinking rapidly for the last few decades."

The turkey (Meleagris gallopavo) was independently domesticated in Mesoamerica and the Southwest, the latter as the only case of Native American animal domestication north of Mexico. In the upland (non-desert) portion of the American Southwest, distinctive closely related mtDNA lineages belonging to haplogroup H1 (thought to indicate domestication) occur from ca. 1 A.D. (Basketmaker II period) through early historic times. At many sites, low frequencies of lineages belonging to haplogroup H2 also occur, apparently derived from the local Merriam’s subspecies. We report genetic, stable isotope, and coprolite data from turkey remains recovered at three early sites in SE Utah and SW Colorado dating to the Basketmaker II, III, and early Pueblo II periods. Evidence from these and other early sites indicates that both the H1 and H2 turkeys had a predominantly maize-based diet similar to that of humans; prior to late Pueblo II times, the birds were kept primarily to provide feathers for bla...

Intensity-duration-frequency (IDF) curves are among the most demandable information in meteorology, hydrology and engineering water resources design, planning, operation, and management works. The IDF Curves accessible are for the most part done by fitting arrangement of yearly greatest precipitation force to parametric dispersions. Intensity-duration-frequency (IDF) curves represent the relationship between storm intensity, storm duration and return period. Environmental change is relied upon to intensify the boundaries in the atmosphere factors. Being prone to harsh climate impacts, it is very crucial to study extreme rainfall-induced flooding for short durations over regions that are rapidly growing. One way to approach the extremes is by the application of the Intensity-Duration-Frequency (IDF) curves. The annual maximum rainfall intensity (AMRI) characteristics are often used to construct these IDF curves that are being used in several infrastructure designs for urban areas. Thus, there is a necessity to obtain high temporal and spatial resolution rainfall information. Many urban areas of developing countries lack long records of short-duration rainfall. The shortest duration obtained is normally at a daily scale/24 h. This paper suggests their generation based on annual daily maximum rainfall (ADMR) records. Rainfall data of 23 (Twenty three) hydrological years of all stations were used. Maximum rainfall frequency analysis was made by Log-Normal Distribution method.

The IDF Curves accessible are for the most part done by fitting arrangement of yearly greatest precipitation force to parametric dispersions. Intensity-duration-frequency (IDF) curves represent the relationship between storm intensity, storm duration and return period. Environmental change is relied upon to intensify the boundaries in the atmosphere factors. Being prone to harsh climate impacts, it is very crucial to study extreme rainfall-induced flooding for short durations over regions that are rapidly growing. One way to approach the extremes is by the application of the Intensity-Duration-Frequency (IDF) curves. The annual maximum rainfall intensity (AMRI) characteristics are often used to construct these IDF curves that are being used in several infrastructure designs for urban areas. Thus, there is a necessity to obtain high temporal and spatial resolution rainfall information. Many urban areas of developing countries lack long records of short-duration rainfall. The shortest duration obtained is normally at a daily scale/24 h. Thus, it is very crucial to find a methodology to construct IDF curves for short-duration rainfall (sub-daily) for these urban areas. The fast extension of urban area that does not have adequate preparedness to cope with climate change is certainly a big risk to life and economy. The study region lies in Karnataka India. The sub-daily IDF curves for current and future climate for the region were constructed from 1 to 24 h based on the Normal Distribution approach. Rainfall data of 23 (Twenty three) hydrological years of all stations were used. Maximum rainfall frequency analysis was made by Normal Distribution method. Finally Equations were developed for different return periods.

Morphometric analysis of the Watershed is considered to be the most satisfactory method because it enables in understanding of the relationship of various aspects within a drainage basin. In the present study two mini watersheds in Raichur city have been considered Mini-watershed 1 with an area of 519.32 km 2 with highest order stream of 6 it flows through north of city and it joins the streams of Krishna, Mini-Watershed 2 with an area of 360.97 km 2 with highest order stream of 5 it flows through south of city and joins Tungabhadra streams. The values of Stream frequency is 1.07 and 1.03, Form factor 0.35and 0.53, Shape factor 2.84 and 1.90, Elongation Ratio 0.67 and 0.82, Circularity Ratio 0.27 and 0.42, Drainage density 1.26 and 1.30, Length of overland flow 0.40 and 0.38 for Mini-watershed 1 and Mini-watershed 2 respectively.

With climate change, modelling has suggested that increased inaccessibility of forage through snow may endanger some populations of arctic ungulates; however, contemporaneous data on snow-cover conditions, other ecological factors and ungulate responses are lacking at the landscape scale. Researchers have increasingly used remote sensing to map snow cover with higher accuracy, but such tools have not been utilized in research and management of arctic ungulate populations. We estimated field-measured percent snow-covered area (F-SCA) in wintering areas of endangered Peary caribou Rangifer tarandus pearyi in the Bathurst Island complex (BIC) and developed a threshold for a normalized difference snow index (NDSI) using Landsat data.We used our NDSI threshold and another threshold to estimate snow-covered area (SCA) in Peary caribou habitats in the BIC during 1993-2003, compared these estimates with snow data from the nearest weather station and assessed the adequacy of Landsat data for arctic ungulate research. Our calculated NDSI threshold of 0.70 reflected field observations better than the published threshold, and our estimated SCAs showed greater variation between study areas, between years and during snow melt. Estimated SCAs were not correlated with total snowfall or snow depth at the nearest weather station. We conclude that SCA using remotely-sensed data for ungulate habitats would be more useful than weather-station data. Our methods could detect winters with relatively mild snow-cover conditions, but not those with very severe conditions; therefore, we recommend development of NDSI thresholds corresponding to 75%F-SCA, instead of 50%.NDSI-derived SCAmethods should provemore useful for southerly arctic regions where sun angles would be less limiting than in the BIC. Higher resolution imagery may be more suited than Landsat for the assessment of snow cover in arctic ungulate ecology. With climate change, further development of remotely-sensed indices of snow cover, such as NDSI and SCA, should enhance our understanding of how arctic ungulates may or may not adapt.

Terrestrial freshwater runoff strongly influences physical and biogeochemical processes at the fjord scale and can have global impacts when considered at the Greenland scale. We investigate the performance of the HIRHAM5 regional climate model over the catchments delivering freshwater to Tyrolerfjord and Young Sound by comparing to the unique Greenland Ecological Monitoring database of in situ observations from this region. Based on these findings, we estimate and discuss the fraction of runoff originating from glacierized and non-glacierized land delivered at the daily scale between 1996 and 2008. We find that glaciers contributed on average 50–80% of annual terrestrial runoff when considering different sections of Tyrolerfjord–Young Sound, but snowpack depletion on land and consequently runoff happens about one month earlier in the model than observed in the field. The temporal shift in the model is a likely explanation why summer surface salinity in the inner fjord did not correlate to modelled runoff.

The soil conservation service (SCS) methodology for computing direct runoff , using soil-cover-moisture complexes involves the selection of a runoff curve number (CN) for such complex events. This method has been further simplified by introducing an assumption on initial abstraction, with only one unknown parameter CN, which is represented by the potential retention capacity of the watershed (S). In this study, coupled SCN-CN with USLE model was used for the estimation of the runoff and sediment yield for eleven watersheds of different land uses (urban, agricultural, and forest) from Damodar Valley Corporation (DVC), Hazaribagh district, Jharkhand, India. For the validation, runoffsediment yield model is employed to a large set of rainfall-runoff-sediment yield data (68 storm events) observed from eleven watersheds. Model performance was assessed by using Nash and Sutcliffe statistical method. The efficiency of results was varying from 60.42 to 92.99 % for sediment yield and 54.23 to 96.12 % for runoff; this efficiency showed a reliable performance of model for estimating the sediment yield and runoff.

ABSTRACT Use of rainfall anomaly based Standardized Precipitation Index (SPI) and satellite-derived Vegetation Condition Index (VCI) are becoming common to assess the impacts of drought on crops. This study analyzed spatio-temporal intra-seasonal and inter-seasonal relationships for 24 years between rainfall and NDVI and between SPI and VCI to understand crop response to water availability in the Rajasthan State, India. To separate the effect of weather and technology on crop growth over time, a modification in VCI was proposed and called "Trend Adjusted VCI" (VCITadj). The VCITadj was computed for early, mid, late and whole crop seasons by deriving pixel wise crop phenology metrics from NDVI profile. Significant linear relationships were found between NDVI and rainfall but phase of crop season affected the strength of this relationship. The SPI and VCITadj were linearly related in all the four seasons, the strength of relationship improved with the progress of crop season and these relationships were stronger than between rainfall and NDVI. These relationships broke down in irrigated croplands. As a result, the anomaly indices of SPI and VCITadj and their intra-seasonal relationships can be used to study the response of crops to water availability for early detection and better prognosis of agricultural drought.

The ENVISAT mission with a suite of high performance sensors offers some opportunities for mapping snow cover at regional and catchment scale. The geometric resolution of MERIS data and the spectral resolution of AATSR data are suitable for these purposes. A new approach, developed in the framework of the GLASNOWMAP project (ESA-DUP2) for monitoring snow cover in Alpine regions, based on the combined use of MERIS and AATSR observations, and topographic information, is proposed. As MERIS spectral bands are not completely proper for the discrimination of snow from clouds -due to the lack of short wave infrared channels -a multisource classification scheme has been developed to combine the results obtained by the classification of MERIS data with the information on cloud distribution as derived from AATSR data; the integration is performed with the aid of snow elevation distribution as derived from the Digital Elevation Model. A supervised fuzzy statistical classifier (Wang 1990) has b...