scholarly journals Differences in water balance between grassland and forest watersheds using long-term data, derived using the CoupModel

2017 ◽  
Vol 49 (1) ◽  
pp. 72-89 ◽  
Author(s):  
Erik MirHadi Madani ◽  
Per Erik Jansson ◽  
Ian Babelon
Keyword(s):  
Water Balance ◽  
Forest Cover ◽  
Land Use Changes ◽  
Daily Basis ◽  
Discharge Data ◽  
Forest Watersheds ◽  
Set Up ◽  
Similar Good ◽  
The Impact

Abstract To quantify the role of land cover during a period of climate change, the runoff response is studied for Plynlimon in Wales, UK. The main objective was two-fold: (i) to create a protocol for modeling water balance on a daily basis; and (ii) to describe the extent to which the impact of land-use changes can be identified and supported by the long-term monitoring data of runoff from two neighboring watersheds with different land covers. The process-oriented CoupModel platform was used to set up the model with a well-defined uncertainty for selected parameters. The behavioral ensembles were applied to simulated daily discharge data for the period of 1992–2010 using subjective criteria to reduce the prior 35,000 candidates with a random uniform distribution of 40 parameters. The accepted ensemble was reduced to 100 candidates by accepting the best root-mean-square error (RMSE) on the accumulated residuals during the simulation period. Similar good performance for the entire period and both watersheds was obtained. The differences in interception evaporation accounted for the most important differences between forest and grassland. The obtained residual demonstrated that changes in the forest cover had an impact on the water balance during the first part of the simulation period.

scholarly journals The extent of land use impact on water regime 

2011 ◽  
Vol 52 (No. 6) ◽  
pp. 239-244 ◽  
Author(s):  
P. Kovář
Keyword(s):  
Land Use ◽  
Water Balance ◽  
Water Regime ◽  
Land Use Changes ◽  
Subsurface Water ◽  
Rainfall Runoff ◽  
Short Term ◽  
Water Recharge ◽  
The Impact

The paper is focused on the impact of land use changes on water regime. First, an emphasis was given to what extent the main components of the water balance on the experimental catchment Všeminka (region Vsetínské Hills) were influenced. For this reason, the WBCM-5 model was implemented for the period of 10 years in a daily step with a particular reference to simulate the components of direct runoff and of subsurface water recharge. In the selected years of the period 1990–2000, the major changes were made in land use and also the significant fluctuation of rainfall-runoff regimes were observed (e.g. dry year 1992 and flood year 1997). After WBCM-5 parameter calibration it was found that some water balance components can change in relation to substantial land use changes even up to tens of percent in a balance-consideration, i.e. in daily, monthly and yearly or decade values, namely the components of interception and also of direct runoff and of subsurface water recharge. However, a different situation appears when investigating significant short-term rainfall-runoff processes. There were about seven real flood events analysed using the model KINFIL-2 (time step 0.5 hr) during the same period of about 10 years on the same catchment. Furthermore, some land use change positive or negative scenarios were also analysed there. As opposed to long-term water balance analyses, there was never achieved any greater differences in the hydrograph peak or volume than 10%. Summarising, it is always important to distinguish a possible land use change impact in either long-term balance or short-term runoff consideration, otherwise a misunderstanding might be easily made, as can often be found when commenting on the impact on floods in some mass media.

scholarly journals Does afforestation deteriorate haze pollution in Beijing–Tianjin–Hebei (BTH), China?

2018 ◽  
Author(s):  
Xin Long ◽  
Naifang Bei ◽  
Jiarui Wu ◽  
Xia Li ◽  
Tian Feng ◽  
...  
Keyword(s):  
Forest Cover ◽  
Fine Particles ◽  
Control Strategies ◽  
Surface Wind ◽  
Forecast Model ◽  
Surface Wind Speed ◽  
Satellite Measurements ◽  
Haze Pollution ◽  
The Impact

Abstract. Although aggressive emission control strategies have been implemented recently in the Beijing–Tianjin–Hebei area (BTH), China, pervasive and persistent haze still frequently engulfs the region during wintertime. Afforestation in BTH, primarily concentrated in the Taihang and Yanshan Mountains, has constituted one of the controversial factors exacerbating the haze pollution due to its slowdown of the surface wind speed. We report here an increasing trend of forest cover in BTH during 2001–2013 based on long-term satellite measurements and the impact of the afforestation on the fine particles (PM2.5) level. Simulations using the Weather Research and Forecast model with chemistry reveal that the afforestation in BTH since 2001 generally deteriorates the haze pollution in BTH to some degree, enhancing PM2.5 concentrations by up to 6 % on average. Complete afforestation or deforestation in the Taihang and Yanshan Mountains would increase or decrease the PM2.5 level within 15 % in BTH. Our model results also suggest that implementing a large ventilation corridor system would not be effective or beneficial to mitigate the haze pollution in Beijing.

scholarly journals Variations of global and continental water balance components as impacted by climate forcing uncertainty and human water use

2016 ◽  
Vol 20 (7) ◽  
pp. 2877-2898 ◽  
Author(s):  
Hannes Müller Schmied ◽  
Linda Adam ◽  
Stephanie Eisner ◽  
Gabriel Fink ◽  
Martina Flörke ◽  
...  
Keyword(s):  
Water Resources ◽  
Water Balance ◽  
Water Use ◽  
Climate Forcing ◽  
Land Area ◽  
Water Balance Components ◽  
Climate Forcings ◽  
The Impact ◽  
Global Water

Abstract. When assessing global water resources with hydrological models, it is essential to know about methodological uncertainties. The values of simulated water balance components may vary due to different spatial and temporal aggregations, reference periods, and applied climate forcings, as well as due to the consideration of human water use, or the lack thereof. We analyzed these variations over the period 1901–2010 by forcing the global hydrological model WaterGAP 2.2 (ISIMIP2a) with five state-of-the-art climate data sets, including a homogenized version of the concatenated WFD/WFDEI data set. Absolute values and temporal variations of global water balance components are strongly affected by the uncertainty in the climate forcing, and no temporal trends of the global water balance components are detected for the four homogeneous climate forcings considered (except for human water abstractions). The calibration of WaterGAP against observed long-term average river discharge Q significantly reduces the impact of climate forcing uncertainty on estimated Q and renewable water resources. For the homogeneous forcings, Q of the calibrated and non-calibrated regions of the globe varies by 1.6 and 18.5 %, respectively, for 1971–2000. On the continental scale, most differences for long-term average precipitation P and Q estimates occur in Africa and, due to snow undercatch of rain gauges, also in the data-rich continents Europe and North America. Variations of Q at the grid-cell scale are large, except in a few grid cells upstream and downstream of calibration stations, with an average variation of 37 and 74 % among the four homogeneous forcings in calibrated and non-calibrated regions, respectively. Considering only the forcings GSWP3 and WFDEI_hom, i.e., excluding the forcing without undercatch correction (PGFv2.1) and the one with a much lower shortwave downward radiation SWD than the others (WFD), Q variations are reduced to 16 and 31 % in calibrated and non-calibrated regions, respectively. These simulation results support the need for extended Q measurements and data sharing for better constraining global water balance assessments. Over the 20th century, the human footprint on natural water resources has become larger. For 11–18% of the global land area, the change of Q between 1941–1970 and 1971–2000 was driven more strongly by change of human water use including dam construction than by change in precipitation, while this was true for only 9–13 % of the land area from 1911–1940 to 1941–1970.

scholarly journals Perubahan Penggunaan Lahan Di Provinsi Lampung Dan Pengaruhnya Terhadap Insidensi Demam Berdarah Dengue (DBD)

2016 ◽  
Vol 4 (3) ◽  
pp. 35
Author(s):  
Agustin Arisandi Mustika ◽  
Samsul Bakri ◽  
Dyah Wulan S. R. Wardani
Keyword(s):  
Land Use ◽  
Forest Cover ◽  
Land Use Changes ◽  
Hemorrhagic Fever ◽  
Forest Area ◽  
Primary Data ◽  
Forest Conversion ◽  
Housing Conditions ◽  
Poverty Level ◽  
The Impact

The conversion of forest area into non-forest area generally can causing the ecology and micro climate change especially rainfall.   The impact of these changes in other side can increasing the probability in occurrence of vector-born disease such as Aedes aegypti mosquito couse of Dengue Hemorrhagic Fever (DHF).   Besides of environmental factors, poverty level, rainfall, and housing conditions the suspected also affect the incidence of dengue.  This research aimed to determine of changes in forest cover and land, poverty level, and housing conditions as well as the impact to the incidence of dengue fever in Lampung. Data collected included primary data of land use changes of Lampung Province and the secondary  data  such  as  the  data  of  precipitation  rapid,  poverty  level,  healthy  house proportion and Incidence Rate of dengue.  The dynamic of changes in forest cover and landper distric/city identified through by Landsat image interpretation 5, 7 and 8  in 2002, 2009 and 2014.   While the impact on DHF analyzed using multiple linear models.   The results showed that there was a significant relationship between the changes of the people forest cover   -1,2634   (p=0,001),   intensive   agricultural   0,5315   (p=0,016),   the   number   of precipitation rapid 0,06869 (p=0,087) and the poverty level -0,2213 (p=0,038) and urbanism region in the towns and villages 28,75 (p=0,010) toward the incidence of dengue in Lampung from the year 2003 to 2014.  Based on the reseacrh result that the goverment should be able to increase the percentage of forest area cause able to decrease the incidence DHF. Keyword: forest conversion, incidence DHF, land use changes

scholarly journals MODELING PRECIPITATION DEPENDENT FOREST RESILIENCE IN INDIA

2018 ◽  
Vol XLII-3 ◽  
pp. 263-266 ◽  
Author(s):  
P. Das ◽  
M. D. Behera ◽  
P. S. Roy
Keyword(s):  
Forest Cover ◽  
Vegetation Type ◽  
Annual Precipitation ◽  
Mean Annual Precipitation ◽  
High Tendency ◽  
North East India ◽  
North East ◽  
Forest Resilience ◽  
The Impact

The impact of long term climate change that imparts stress on forest could be perceived by studying the regime shift of forest ecosystem. With the change of significant precipitation, forest may go through density change around globe at different spatial and temporal scale. The 100 class high resolution (60 meter spatial resolution) Indian vegetation type map was used in this study recoded into four broad categories depending on phrenology as (i) forest, (ii) scrubland, (iii) grassland and (iv) treeless area. The percentage occupancy of forest, scrub, grass and treeless were observed as 19.9&amp;thinsp;%, 5.05&amp;thinsp;%, 1.89&amp;thinsp;% and 7.79&amp;thinsp;% respectively. Rest of the 65.37&amp;thinsp;% land area was occupied by the cropland, built-up, water body and snow covers. The majority forest cover were appended into a 5&amp;thinsp;km&amp;thinsp;&amp;times;&amp;thinsp;5&amp;thinsp;km grid, along with the mean annual precipitation taken from Bioclim data. The binary presence and absence of different vegetation categories in relates to the annual precipitation was analyzed to calculate their resilience expressed in probability values ranging from 0 to 1. Forest cover observed having resilience probability (Pr) &amp;lt;&amp;thinsp;0.3 in only 0.3&amp;thinsp;% (200&amp;thinsp;km<sup>2</sup>) of total forest cover in India, which was 4.3&amp;thinsp;% &amp;lt;&amp;thinsp;0.5&amp;thinsp;Pr. Majority of the scrubs and grass (64.92&amp;thinsp;% Pr&amp;thinsp;&amp;lt;&amp;thinsp;0.5) from North East India which were the shifting cultivation lands showing low resilience, having their high tendency to be transform to forest. These results have spatial explicitness to highlight the resilient and non-resilient distribution of forest, scrub and grass, and treeless areas in India.

scholarly journals Water Balance Backward: Estimation of Annual Watershed Precipitation and Its Long-Term Trend with the Help of the Calibration-Free Generalized Complementary Relationship of Evaporation

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1775
Author(s):  
Jozsef Szilagyi
Keyword(s):  
Water Balance ◽  
Mean Squared Error ◽  
Linear Trend ◽  
Free Water ◽  
The United States ◽  
Discharge Data ◽  
Complementary Relationship ◽  
Stream Discharge ◽  
Calibration Free

Watershed-scale annual evapotranspiration (ET) is routinely estimated by a simplified water balance as the difference in catchment precipitation (P) and stream discharge (Q). With recent developments in ET estimation by the calibration-free generalized complementary relationship, the water balance equation is employed to estimate watershed/basin P at an annual scale as ET + Q on the United States (US) Geological Survey’s Hydrologic Unit Code (HUC) 2- and 6-level watersheds over the 1979–2015 period. On the HUC2 level, mean annual PRISM P was estimated with a correlation coefficient (R) of 0.99, relative bias (RB) of zero, root-mean-squared-error (RMSE) of 54 mm yr−1, ratio of standard deviations (RS) of 1.08, and Nash–Sutcliffe efficiency (NSE) of 0.98. On the HUC6 level, R, RS, and NSE hardly changed, RB remained zero, while RMSE increased to 90 mm yr−1. Even the long-term linear trend values were found to be fairly consistent between observed and estimated values with R = 0.97 (0.81), RMSE = 0.63 (1.63) mm yr−1, RS = 0.99 (1.05), NSE = 0.92 (0.59) on the HUC2 and HUC6 (in parentheses) levels. This calibration-free water-balance method demonstrates that annual watershed precipitation can be estimated with an acceptable accuracy from standard atmospheric/radiation and stream discharge data.

scholarly journals Expected performances of the Characterising Exoplanet Satellite (CHEOPS)

2020 ◽  
Vol 635 ◽  
pp. A22 ◽  
Author(s):  
A. Deline ◽  
D. Queloz ◽  
B. Chazelas ◽  
M. Sordet ◽  
F. Wildi ◽  
...  
Keyword(s):  
Light Curve ◽  
High Precision ◽  
Background Level ◽  
Monte Carlo Algorithm ◽  
Complete Analysis ◽  
Transiting Planets ◽  
End To End ◽  
Set Up ◽  
The Impact

Context. The characterisation of Earth-size exoplanets through transit photometry has stimulated new generations of high-precision instruments. In that respect, the Characterising Exoplanet Satellite (CHEOPS) is designed to perform photometric observations of bright stars to obtain precise radii measurements of transiting planets. The CHEOPS instrument will have the capability to follow up bright hosts provided by radial-velocity facilities. With the recent launch of the Transiting Exoplanet Survey Satellite (TESS), CHEOPS may also be able to confirm some of the long-period TESS candidates and to improve the radii precision of confirmed exoplanets. Aims. The high-precision photometry of CHEOPS relies on careful on-ground calibration of its payload. For that purpose, intensive pre-launch campaigns of measurements were carried out to calibrate the instrument and characterise its photometric performances. This work reports on the main results of these campaigns. It provides a complete analysis of data sets and estimates in-flight photometric performance by means of an end-to-end simulation. Instrumental systematics were measured by carrying out long-term calibration sequences. Using an end-to end model, we simulated transit observations to evaluate the impact of in-orbit behaviour of the satellite and to determine the achievable precision on the planetary radii measurement. Methods. After introducing key results from the payload calibration, we focussed on the data analysis of a series of long-term measurements of uniformly illuminated images. The recorded frames were corrected for instrumental effects and a mean photometric signal was computed on each image. The resulting light curve was corrected for systematics related to laboratory temperature fluctuations. Transit observations were simulated, considering the payload performance parameters. The data were corrected using calibration results and estimates of the background level and position of the stellar image. The light curve was extracted using aperture photometry and analysed with a transit model using a Markov chain Monte Carlo algorithm. Results. In our analysis, we show that the calibration test set-up induces thermally correlated features in the data that can be corrected in post-processing to improve the quality of the light curves. We find that on-ground photometric performances of the instrument measured after this correction is of the order of 15 parts per million over five hours. Using our end-to-end simulation, we determine that measurements of planet-to-star radii ratio with a precision of 2% for a Neptune-size planet transiting a K-dwarf star and 5% for an Earth-size planet orbiting a Sun-like star are possible with CHEOPS. These values correspond to transit depths obtained with signal-to-noise ratios of 25 and 10, respectively, allowing the characterisation and detection of these planets. The pre-launch CHEOPS performances are shown to be compliant with the mission requirements.

scholarly journals Investigating soil moisture-climate interactions with prescribed soil moisture experiments: an assessment with the Community Earth System Model (version 1.2)

2016 ◽  
Author(s):  
Mathias Hauser ◽  
René Orth ◽  
Sonia I. Seneviratne
Keyword(s):  
Soil Moisture ◽  
Water Balance ◽  
Land Surface ◽  
Seasonal Cycle ◽  
Deep Soil ◽  
Surface Hydrology ◽  
Climate Interactions ◽  
Set Up ◽  
Moisture Conditions ◽  
The Impact

Abstract. Land surface hydrology is an important control of surface weather and climate. A valuable technique to investigate this link is the prescription of soil moisture in land surface models, which leads to a decoupling of the interaction between the atmosphere and land processes. Diverse approaches to prescribe soil moisture, as well as different prescribed soil moisture conditions can be envisaged. Here, we compare and assess three methodologies to prescribe soil moisture and investigate the impact of two estimates of the climatological seasonal cycle to prescribe soil moisture. This can help to guide the set up of future experiments prescribing soil moisture, as for instance planned within the "Land Surface, Snow and Soil Moisture Model Intercomparison Project" (LS3MIP). Our analysis shows that, though in appearance similar, the different approaches require substantially different long-term moisture inputs and lead to different temperature signals. The smallest influence on temperature and the water balance is found when prescribing the median seasonal cycle of deep soil liquid water, whereas the strongest signal is found when prescribing soil liquid and soil ice using the mean seasonal cycle. These results indicate that induced net water-balance perturbations in experiments investigating soil moisture-climate coupling are important contributors to the climate response, in addition to the intended impact of the decoupling.

scholarly journals 60 years of UK visibility measurements: impact of meteorology and atmospheric pollutants on visibility

2017 ◽  
Vol 17 (3) ◽  
pp. 2085-2101 ◽  
Author(s):  
Ajit Singh ◽  
William J. Bloss ◽  
Francis D. Pope
Keyword(s):  
Relative Humidity ◽  
Aerosol Particle ◽  
Urban Areas ◽  
Land Use Changes ◽  
Gas Absorption ◽  
Atmospheric Pollutants ◽  
Light Extinction ◽  
The Impact ◽  
Aerosol Hygroscopicity

Abstract. Reduced visibility is an indicator of poor air quality. Moreover, degradation in visibility can be hazardous to human safety; for example, low visibility can lead to road, rail, sea and air accidents. In this paper, we explore the combined influence of atmospheric aerosol particle and gas characteristics, and meteorology, on long-term visibility. We use visibility data from eight meteorological stations, situated in the UK, which have been running since the 1950s. The site locations include urban, rural and marine environments. Most stations show a long-term trend of increasing visibility, which is indicative of reductions in air pollution, especially in urban areas. Additionally, the visibility at all sites shows a very clear dependence on relative humidity, indicating the importance of aerosol hygroscopicity on the ability of aerosol particles to scatter radiation. The dependence of visibility on other meteorological parameters, such as wind speed and wind direction, is also investigated. Most stations show long-term increases in temperature which can be ascribed to climate change, land-use changes (e.g. urban heat island effects) or a combination of both; the observed effect is greatest in urban areas. The impact of this temperature change upon local relative humidity is discussed. To explain the long-term visibility trends and their dependence on meteorological conditions, the measured data were fitted to a newly developed light-extinction model to generate predictions of historic aerosol and gas scattering and absorbing properties. In general, an excellent fit was achieved between measured and modelled visibility for all eight sites. The model incorporates parameterizations of aerosol hygroscopicity, particle concentration, particle scattering, and particle and gas absorption. This new model should be applicable and is easily transferrable to other data sets worldwide. Hence, historical visibility data can be used to assess trends in aerosol particle properties. This approach may help constrain global model simulations which attempt to generate aerosol fields for time periods when observational data are scarce or non-existent. Both the measured visibility and the modelled aerosol properties reported in this paper highlight the success of the UK's Clean Air Act, which was passed in 1956, in cleaning the atmosphere of visibility-reducing pollutants.

Sign in / Sign up

Export Citation Format

Share Document