scholarly journals Evaluating MODIS Dust-Detection Indices over the Arabian Peninsula

2018 ◽  
Vol 10 (12) ◽  
pp. 1993 ◽  
Author(s):  
Sarah Albugami ◽  
Steven Palmer ◽  
Jeroen Meersmans ◽  
Toby Waine
Keyword(s):  
Land Cover ◽  
Agricultural Land ◽  
Arabian Peninsula ◽  
Source Region ◽  
Temporal Trends ◽  
Dust Storms ◽  
Storm Events ◽  
Near Surface ◽  
Airborne Dust ◽  
Land Cover Types

Sand and dust storm events (SDEs), which result from strong surface winds in arid and semi-arid areas, exhibiting loose dry soil surfaces are detrimental to human health, agricultural land, infrastructure, and transport. The accurate detection of near-surface dust is crucial for quantifying the spatial and temporal occurrence of SDEs globally. The Arabian Peninsula is an important source region for global dust due to the presence of extensive deserts. This paper evaluates the suitability of five different MODIS-based methods for detecting airborne dust over the Arabian Peninsula: (a) Normalized Difference Dust Index (NDDI); (b) Brightness Temperature Difference (BTD) (31–32); (c) BTD (20–31); (d) Middle East Dust Index (MEDI) and (e) Reflective Solar Band (RSB). We derive detection thresholds for each index by comparing observed values for ‘dust-present’ versus ‘dust-free’ conditions, taking into account various land cover settings and analyzing associated temporal trends. Our results suggest that the BTD (31–32) method and the RSB index are the most suitable indices for detecting dust storms over different land-cover types across the Arabian Peninsula. The NDDI and BTD (20–31) methods have limitations in identifying dust over multiple land-cover types. Furthermore, the MEDI has been found to be unsuitable for detecting dust in the study area across all land-cover types.

scholarly journals A Multivariate and Spatiotemporal Analysis of Water Quality in Code River, Indonesia

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Mochamad A. Pratama ◽  
Yan D. Immanuel ◽  
Dwinanti R. Marthanty
Keyword(s):  
Water Quality ◽  
Land Cover ◽  
Agricultural Land ◽  
Water Quality Management ◽  
Temporal Trends ◽  
Oxygen Demand ◽  
Principal Component ◽  
Water Quality Monitoring ◽  
Quality Data ◽  
Water Quality Data

The efficacy of a water quality management strategy highly depends on the analysis of water quality data, which must be intensively analyzed from both spatial and temporal perspectives. This study aims to analyze spatial and temporal trends in water quality in Code River in Indonesia and correlate these with land use and land cover changes over a particular period. Water quality data consisting of 15 parameters and Landsat image data taken from 2011 to 2017 were collected and analyzed. We found that the concentrations of total dissolved solid, nitrite, nitrate, and zinc had increasing trends from upstream to downstream over time, whereas concentrations of parameter biological oxygen demand, cuprum, and fecal coliform consistently undermined water quality standards. This study also found that the proportion of natural vegetation land cover had a positive correlation with the quality of Code River’s water, whereas agricultural land and built-up areas were the most sensitive to water pollution in the river. Moreover, the principal component analysis of water quality data suggested that organic matter, metals, and domestic wastewater were the most important factors for explaining the total variability of water quality in Code River. This study demonstrates the application of a GIS-based multivariate analysis to the interpretation of water quality monitoring data, which could aid watershed stakeholders in developing data-driven intervention strategies for improving the water quality in rivers and streams.

scholarly journals Impact of Land Cover Types on Riverine CO2 Outgassing in the Yellow River Source Region

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2243
Author(s):  
Mingyang Tian ◽  
Xiankun Yang ◽  
Lishan Ran ◽  
Yuanrong Su ◽  
Lingyu Li ◽  
...  
Keyword(s):  
Climate Change ◽  
Land Cover ◽  
Yellow River ◽  
Stream Water ◽  
Source Region ◽  
The Yellow River ◽  
Co2 Efflux ◽  
Land Cover Types ◽  
Yellow River Source ◽  
Alpine Rivers

Under the context of climate change, studying CO2 emissions in alpine rivers is important because of the large carbon storage in these terrestrial ecosystems. In this study, riverine partial pressure of CO2 (pCO2) and CO2 emission flux (FCO2) in the Yellow River source region (YRSR) under different landcover types, including glaciers, permafrost, peatlands, and grasslands, were systematically investigated in April, June, August, and October 2016. Relevant chemical and environmental parameters were analyzed to explore the primary controlling factors. The results showed that most of the rivers in the YRSR were net CO2 source, with the pCO2 ranging from 181 to 2441 μatm and the FCO2 ranging from −50 to 1574 mmol m−2 d−1. Both pCO2 and FCO2 showed strong spatial and temporal variations. The highest average FCO2 was observed in August, while the lowest average was observed in June. Spatially, the lowest FCO2 were observed in the permafrost regions while the highest FCO2 were observed in peatland. By integrating seasonal changes of the water surface area, total CO2 efflux was estimated to be 0.30 Tg C year−1. This indicates that the YRSR was a net carbon source for the atmosphere, which contradicts previous studies that conclude the YRSR as a carbon sink. More frequent measurements of CO2 fluxes, particularly through several diel cycles, are necessary to confirm this conclusion. Furthermore, our study suggested that the riverine dissolved organic carbon (DOC) in permafrost (5.0 ± 2.4 mg L−1) is possibly derived from old carbon released from permafrost melting, which is equivalent to that in peatland regions (5.1 ± 3.7 mg L−1). The degradation of DOC may have played an important role in supporting riverine CO2, especially in permafrost and glacier-covered regions. The percent coverage of corresponding land cover types is a good indicator for estimating riverine pCO2 in the YRSR. In view of the extensive distribution of alpine rivers in the world and their sensitivity to climate change, future studies on dynamics of stream water pCO2 and CO2 outgassing are strongly needed to better understand the global carbon cycle.

scholarly journals Comparison of thermal behaviour of different land cover types in Slovenia and Czech Republic

Dela ◽  
2019 ◽  
pp. 111-134
Author(s):  
Miroslav Vysoudil ◽  
Karolina Kácovská ◽  
Darko Ogrin
Keyword(s):  
Czech Republic ◽  
Land Cover ◽  
Surface Temperature ◽  
Thermal Behaviour ◽  
Hot Spots ◽  
Agricultural Land ◽  
The Czech Republic ◽  
Land Cover Types ◽  
Green Vegetation ◽  
Cold Spots

This paper presents the results of a study of thermal behaviour of different land cover types in the Czech Republic and Slovenia. A hand-held thermal camera, Fluke Ti55, was used for data collection. Variation in the values of the surface temperature characteristics reflects the geographically dissimilar spaces. The investigation demonstrated impact of dense green vegetation and water bodies on the balanced thermal behaviour of landscapes in both countries. Thus, they appear to be cold spots with the lowest values. The most obvious variation in surface temperature is associated with artificial areas and bare surfaces. They usually represent hot spots in the landscape. In both countries similar thermal behaviour was found in artificial land cover types as opposed to agricultural land cover types.

scholarly journals Meteorological conditions during extreme wind erosion events on heavy soils

2010 ◽  
Vol 58 (1) ◽  
pp. 115-122
Author(s):  
Bronislava Mužíková ◽  
Tomáš Středa ◽  
Jana Podhrázská ◽  
František Toman
Keyword(s):  
Snow Cover ◽  
Air Temperature ◽  
Wind Erosion ◽  
Agricultural Land ◽  
Freezing Point ◽  
Meteorological Conditions ◽  
Dust Storms ◽  
Crop Damage ◽  
Positive Temperature ◽  
Airborne Dust

Wind erosion in the Czech Republic conditions poses relatively a lot of danger, especially for the most fertile areas, where agricultural land is more vulnerable due to the large pieces of land and inappropriate crop rotation. This process causes damage to agriculture by loss of topsoil, fertilizers, seeds and crop damage as well as sedimentation in water recipients and on roads. It also has negative impacts on human health (airborne dust). Wind erosion is especially affected by climatic elements (wind, temperature, precipitation and evaporation etc.) and soil characteristics (soil type, content of erodible particles, soil moisture). Wind erosion affects mainly light and medium heavy soil. South Moravia is an example of the territories to which this rule does not apply. Although soils in the Carpathian flysch subsoil are mainly heavy, erosion has been causing damage here for many decades. Quite strong dust storms are not rare, especially at the end of winter and in early spring when the soil is not covered by vegetation.Notable cases of dust storms in the area were recorded in local chronicles, and then written in the summary publication by dr. Švehlík. Interest of this publication was focused on the most destructive cases of dust storms in Bílé Karpaty foothills. The aim was to study meteorological conditions during the period before and during the occurrence of dust storms in the area in detail and to find the relationship between weather and the intensity of wind erosion. The data of wind speed and direction, temperature, precipitation and snow were evaluated. In all cases the average daily air temperature and ground air temperature was over the freezing point or closely under it. The temperature generally increased before the dust storm occurrence and it often happened from negative to positive temperature and the soil probably defrosted. Snow cover was very small or there was no snow cover at all. In the course of April wind erosion occurrence there was no snow and the precipitation was inconsiderable. Soil at the station was mostly bare, dry and defrosted.

Summertime dust storms over the Arabian Peninsula and impacts on radiation and atmospheric circulation.

2021 ◽  
Author(s):  
Diana Francis ◽  
Jean-Pierre Chaboureau ◽  
Narendra Nelli ◽  
Juan Cuesta ◽  
Noor Alshamsi
Keyword(s):  
Dust Storm ◽  
Radiative Forcing ◽  
Arabian Peninsula ◽  
Source Region ◽  
Dust Storms ◽  
Dimensional Structure ◽  
Climate Projections ◽  
Air Quality Forecast ◽  
The Impact ◽  
First Time

<p>This study investigates the underlying atmospheric dynamics associated with intense dust storms in summer 2018 over the Arabian Peninsula (AP); a major dust source at global scale. It reports, for the first time, on the formation of cyclone over the Empty Quarter Desert as important mechanism for intense dust storms over this source region. The dust direct and semi-direct radiative forcings are observed, for the first time over this source region, using high-resolution in-situ and CERES-SYN satellite observational data. The three-dimensional structure and evolution of the dust storms are inferred from state-of-the-art satellite products such as SEVIRI, AEROIASI and CALIPSO. The dynamics and thermodynamics of the boundary layer during this event are thoroughly analyzed using ERA5 reanalysis and ground based observations.</p><p>We found that a large dust storm by Shamal winds led up, through radiative forcing, to cyclone development over the Empty Quarter Desert, subsequent dust emissions, development of convective clouds and rain. The cyclogenesis over this region initiated a second intense dust storm which developed and impacted the AP for 3 consecutive days. The uplifted dust by the cyclone reached 5 km in altitude and altered the radiative budget at the surface, inducing both significant warming during night and cooling during day. The dust load uplifted by the cyclone was estimated by the mesoscale model Meso-NH to be in the order of 20 Tg, and the associated aerosol optical depth was higher than 3. The model simulates reasonably the radiative impact of the dust in the shortwave but highly underestimated its impact in the LW.</p><p>Our study stresses the importance of the dust radiative forcing in the longwave and that it should be accurately accounted for in models to properly represent the impact of dust on the Earth system especially near source areas. Missing the warming effect of dust aerosols would impact both the weather and air quality forecast, and the regional climate projections.</p><p>These results were published in November 2020 in the journal Atmospheric Research doi.org/10.1016/j.atmosres.2020.105364.</p>

scholarly journals Investigating the Effect of the “Land between the Lakes” on Storm Patterns

2014 ◽  
Vol 53 (6) ◽  
pp. 1506-1524 ◽  
Author(s):  
Josh Durkee ◽  
Ahmed M. Degu ◽  
Faisal Hossain ◽  
Rezaul Mahmood ◽  
Jesse Winchester ◽  
...  
Keyword(s):  
Forest Cover ◽  
Agricultural Land ◽  
Open Water ◽  
Mississippi Valley ◽  
Storm Events ◽  
Hysplit Model ◽  
Near Surface ◽  
Synoptic Classification ◽  
Synoptic Conditions ◽  
Convective Cells

AbstractThe artificially created region around the “Land between the Lakes” (LBL) in Kentucky represents unique land use and land cover (LULC) heterogeneities. Over a distance of 100 km, the LULC comprises artificially created open water bodies (i.e., two parallel large run-on-river dams separated by the LBL), mountainous terrain, forest cover, and extensive agricultural land. Such heterogeneities increase (decrease) moisture supply and sensible heat, resulting in a differential air mass boundary that helps to initiate (inhibit) convection. Hence, the LBL can potentially modify precipitation formation. Historical anecdotes reveal a tendency for storms to dissipate or reintensify near the LBL. The specific scientific question pursued in this study is therefore the following: Has the unique development of two parallel run-on-river reservoirs and the surrounding LULC heterogeneity modified storm patterns in the region? Ten storm events during the growing season were selected. Two additional events, observed by the newly established high-resolution Kentucky Mesonet network, were also considered. Radar reflectivity images were visually inspected to understand the evolution of convective cells that originated or were modified near the LBL. The Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) Model was used to determine near-surface trajectories that led to the selected events. The spatial synoptic classification and merged Geostationary Operational Environmental Satellite (GOES) IR images were analyzed to determine the prevailing synoptic conditions on the event dates. Six storm events showed a pattern wherein the convective cells lost strength as it passed over the LBL in a northeasterly direction. In two events, Next Generation Weather Radar (NEXRAD) reflectivity imagery revealed enhancement of convection as the storm passed over the LBL toward the Mississippi valley. Further dissection of the storm morphology suggested that the thermodynamic environment may have played an important role for the eight events where modification of precipitation near LBL has been clearly observed.

scholarly journals The impact of Pacific Decadal Oscillation on springtime dust activity in Syria

2016 ◽  
Author(s):  
Bing Pu ◽  
Paul Ginoux
Keyword(s):  
Middle East ◽  
Optical Depth ◽  
North Africa ◽  
Pacific Decadal Oscillation ◽  
Large Scale ◽  
Arabian Peninsula ◽  
Dust Storms ◽  
Near Surface ◽  
Deep Blue ◽  
The Impact

Abstract. The increasing trend of aerosol optical depth in the Middle East and a recent severe dust storm in Syria have raised questions as whether dust storms will increase and promoted investigations on the dust activities driven by the natural climate variability underlying the ongoing human perturbations such as the Syrian civil war. This study examined the influences of the Pacific decadal oscillation (PDO) on dust activities in Syria using an innovative dust optical depth (DOD) dataset derived from Moderate Resolution Imaging Spectroradiometer (MODIS) Deep Blue aerosol products. A significantly negative correlation is found between the Syrian DOD and the PDO in spring from 2003–2015. High DOD in spring is associated with lower geopotential height over the Middle East, Europe, and North Africa, accompanied by near surface anomalous westerly winds over the Mediterranean basin and southerly winds over the eastern Arabian Peninsula. These large-scale patterns promote the formation of the cyclones over the Middle East to trigger dust storms and also facilitate the transport of dust from North Africa, Iraq, and Saudi Arabian to Syria, where the transported dust dominates the seasonal mean DOD in spring. A negative PDO not only creates circulation anomalies favorable to high DOD in Syria but also suppresses precipitation in dust source regions over the eastern and southern Arabian Peninsula and northeastern Africa. On the daily scale, in addition to the favorable large-scale condition associated with a negative PDO, enhanced atmospheric instability in Syria associated with increased precipitation in Turkey and northern Syria is also critical for the development of strong springtime dust storms in Syria.

Application of the complete CORINE land covers for modelling in WRF model

2021 ◽  
Author(s):  
Hajnalka Breuer ◽  
Zsuzsanna Zempléni ◽  
Ákos Varga
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Land Surface ◽  
Wrf Model ◽  
Hungarian Academy ◽  
Substantial Effect ◽  
Convective Precipitation ◽  
Near Surface ◽  
Land Cover Types ◽  
One Year

<p>Land use information is crucial in weather modelling as it determines the energy partitioning of the land surface. Based on the partitioning heating of near surface air and moisture supply of the planetary boundary layer is determined. These processes affect the general calculation of temperature, but it also has substantial effect on precipitation formation, especially on convective precipitation.</p><p>In this study the CORINE 44 categories are integrated into the WRF model. Usually the 44 land cover types are recategorized into a standard USGS or MODIS land use types. Here we present a dataset and application with the complete integration of the 44 types.</p><p>One-year runs are created with the CORINE land cover compared to the standard USGS dataset. Along with the new land cover types vegetation parameters had be defined as well. Four runs refer to a USGS-reference, CORINE2USGS converted, CORINE-USGS parameter, CORINE-newparameters where the effect of land cover and parameter change is analyzed. The modelled area covers the whole European region with 50 km resolution using the WRF 4.2 model. Regionally, on a monthly average 5-30% difference in precipitation and around 1 °C differences occur.</p><p>The research was supported by the Hungarian National Research, Development and Innovation Office, Grant No. FK132014. Hajnalka Breuer's work was additionally financed by the János Bolyai Research Scholarship of the Hungarian Academy of Sciences.</p>

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