scholarly journals ESTIMATION OF BVOC EMISSIONS IN GUANGZHOU AND ITS SPATIAL-TEMPORAL VARIATIONS: PRELIMINARY RESULTS FROM GLOBEIS

2018 ◽  
Vol XLII-3/W5 ◽  
pp. 33-38
Author(s):  
L. Li ◽  
Y. Wang ◽  
Y. Zheng ◽  
T. Chen
Keyword(s):  
Land Cover ◽  
Meteorological Data ◽  
Seasonal Pattern ◽  
Temporal Variations ◽  
Emission Rates ◽  
Area Index ◽  
Land Cover Types ◽  
The North ◽  
Result Show ◽  
High Emission

<p><strong>Abstract.</strong> Biogenic VOC emissions greatly exceed anthropogenic emissions and are regarded as significant precursors to secondary organic aerosol (SOA) and ozone. Using the Global Biosphere Emission and Interactions System (GloBEIS) model, 1<span class="thinspace"></span>&amp;times;<span class="thinspace"></span>1<span class="thinspace"></span>km gridded and hourly BVOC emissions in Guangzhou were estimated for the year of 2012. This study used satellite-retrieved land cover data, cloud product and leaf area index (LAI), observed meteorological data and local emission rates for land cover types in South China. The result show that the total BVOC emission in Guangzhou, 2012 was 4.39<span class="thinspace"></span>kt and the average area emission was 5.93<span class="thinspace"></span>t/(km<sup>2</sup>&amp;sdot;a), of which isoprene contributed about 55.7% (2.44<span class="thinspace"></span>kt)), monoterpenes about 11.9% (0.52<span class="thinspace"></span>kt) and OVOC about 32.4% (1.42<span class="thinspace"></span>kt). Emission factors of land cover types and correction parameters including LAI, wind speed and relative humidity have great effects on the estimation results of the model. BVOC emissions in Guangzhou exhibit a marked monthly and seasonal pattern with the peak emission in July to August and the lowest emission in January and are mainly distributed in the east-western of Conghua, the north of Zengcheng and the border of Huadu and Conghua, mostly covered by evergreen broadleaf forest with high emission factor, while areas of BVOC emission below 50<span class="thinspace"></span>kg/(km<sup>2</sup>&amp;sdot;a) are distributed in highly urbanized areas like Tianhe, Yuexiu, Liwan and Haizhu district.</p>

Estimation of the average district winter wheat yield based on satellite and ground meteorological data

2020 ◽  
Vol 3 ◽  
pp. 103-121
Author(s):  
A.D. Kleschenko ◽  
◽  
O.V. Savitskaya ◽  
S.A. Kosyakin ◽  
◽  
...  
Keyword(s):  
Winter Wheat ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Meteorological Data ◽  
Wheat Yield ◽  
Condition Index ◽  
Area Index ◽  
The North ◽  
Independent Information ◽  
Winter Wheat Yield

The research results of the dependence of the average district winter wheat yield on satellite and ground meteorological information for the subjects of the North Caucasian and Volga UGMS are presented. The following satellite indices were used in the work: NDVI (Normalized Difference Vegetation Index), VCI (Vegetation Condition Index) and LAI (Leaf Area Index). The method of interpolation of inverse weighted squares of distances for obtain a set of meteorological parameters for districts there were no weather stations was used. Districts for taking into account agroclimatic conditions were combined into groups using Shashko's Agroclimatic Regionalization method. The selection of parameters that have the greatest impact on the yield was carried out using the correlation-regression analysis method. The corresponding regression models were obtained for the researched regions of the Russian Federation. Verification of the obtained models on dependent and independent information showed a fairly good result. Keywords: NDVI, LAI, interpolation, Shashko's Agroclimatic Regionalization, average district yield, meteorological information Tab. 5. Fig. 7. Ref. 20.

Biological and Environmental Controls on Evaporative Fractions at AmeriFlux Sites

2016 ◽  
Vol 55 (1) ◽  
pp. 145-161 ◽  
Author(s):  
Chunlüe Zhou ◽  
Kaicun Wang
Keyword(s):  
Land Cover ◽  
Latent Heat ◽  
Air Temperature ◽  
Vegetation Index ◽  
Meteorological Data ◽  
Heat Fluxes ◽  
Vegetation Coverage ◽  
Land Cover Types ◽  
Environmental Controls ◽  
Mean Square Errors

AbstractKnowledge of the evaporative fraction (EF: the ratio of latent heat flux to the sum of sensible and latent heat fluxes) and its controls is particularly important for accurate estimates of water flux, heat exchange, and ecosystem response to climatic changes. In this study, the biological and environmental controls on monthly EF were evaluated across 81 AmeriFlux sites, mainly in North America, for 2000–12. The land-cover types of these sites include forest, shrubland, grassland, and cropland, and the local climates vary from humid to arid. The results show that vegetation coverage, indicated by the normalized difference vegetation index (NDVI), has the best agreement with EF (site-averaged partial correlation coefficient ρ = 0.53; significance level p < 0.05) because of vegetation transpiration demand. The minimum air temperature is closely related to EF (site-averaged ρ = 0.51; p < 0.05) because of the inhibition of respiratory enzyme activity. Relative humidity, an indicator of surface aridity, shows a significant positive correlation with EF (site-averaged ρ = 0.46; p < 0.05). The impacts of wind speed and diurnal air temperature range on EF depend on land-cover types and are strong over grasslands and cropland. From these findings, empirical methods were established to predict monthly EF using meteorological data and NDVI. Correlation coefficients between EF estimates and observations range from 0.80 to 0.93, with root-mean-square errors varying from 0.09 to 0.12. This study demonstrates the varying controls on EF across different landscapes and enhances understanding of EF and its dynamics under changing climates.

scholarly journals Mapping Biophysical Parameters for Land Surface Modeling over the Continental US Using MODIS and Landsat

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Lahouari Bounoua ◽  
Ping Zhang ◽  
Kurtis Thome ◽  
Jeffrey Masek ◽  
Abdelmounaime Safia ◽  
...  
Keyword(s):  
Land Cover ◽  
Land Surface ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Climate Modeling ◽  
Surface Fluxes ◽  
Biophysical Parameters ◽  
Area Index ◽  
Spatial And Temporal Scales ◽  
The North

In terms of the space cities occupy, urbanization appears as a minor land transformation. However, it permanently modifies land’s ecological functions, altering its carbon, energy, and water fluxes. It is therefore necessary to develop a land cover characterization at fine spatial and temporal scales to capture urbanization’s effects on surface fluxes. We develop a series of biophysical vegetation parameters such as the fraction of photosynthetically active radiation, leaf area index, vegetation greenness fraction, and roughness length over the continental US using MODIS and Landsat products for 2001. A 13-class land cover map was developed at a climate modeling grid (CMG) merging the 500 m MODIS land cover and the 30 m impervious surface area from the National Land Cover Database. The landscape subgrid heterogeneity was preserved using fractions of each class from the 500 m and 30 m into the CMG. Biophysical parameters were computed using the 8-day composite Normalized Difference Vegetation Index produced by the North American Carbon Program. In addition to urban impact assessments, this dataset is useful for the computation of surface fluxes in land, vegetation, and urban models and is expected to be widely used in different land cover and land use change applications.

scholarly journals The role of forest maturity on catchment hydrologic stability

2016 ◽  
Author(s):  
Oscar Belmar ◽  
José Barquín ◽  
Jose Manuel Álvarez-Martínez ◽  
Francisco J. Peñas ◽  
Manuel Del Jesus
Keyword(s):  
Experimental Design ◽  
Land Cover ◽  
Meteorological Data ◽  
Hydrological Regime ◽  
Land Cover Types ◽  
Low Flows ◽  
Relative Contribution ◽  
Hydrological Variability ◽  
Precipitation Regimes

Abstract. Land cover and soil properties largely determine how climatic and hydrological regimes interact and produce hydrological stress in aquatic ecosystems. This study aims to clarify the influence of forests, as well as other majoritarian land cover types, on hydrological regime through an experimental design without the main limitations associated with traditional paired-watershed studies. With this aim, we use more catchments and an additional forest descriptor: forest maturity. We focus on flood and drought regimes, as they constitute the extremes of hydrological variability. Specific objectives were to isolate the relative contribution of precipitation and land cover composition to such flow extremes and to contrast the effectiveness of forests (surface and maturity) and other land cover types to predict them. The study was developed in a heterogeneous region located in the Cantabrian Mountains (NW Spain) with different vegetation types and a long history of human disturbance and land use change that allowed a robust experimental design. Regression and partial correlation analyses were developed using hydrological and meteorological data combined through hydrological modelling using IHACRES. Land cover characteristics showed ability to predict both flood regimes and low flows, although low flows were explained mainly by precipitation regimes. Forests showed a stabilization effect on flow regime (lower floods and greater base flows), but the effect was more evident with forest maturity than with surface. Other land cover types showed different effects. Evaluating the role of land cover on hydrological stability requires the use of comprehensive information involving different descriptors and their temporal changes, not only the current surface occupied by each land cover type.

scholarly journals Index-based Approach in Relation to Built-up and LST Dynamics; A Study of Lahore, Pakistan

2021 ◽  
Vol 12 (1) ◽  
pp. 32-40
Author(s):  
Kanwal Javid ◽  
Muhammad Ameer Nawaz Akram ◽  
Shazia Pervaiz ◽  
Rumana Siddiqui ◽  
Nausheen Mazhar
Keyword(s):  
Land Cover ◽  
Land Surface ◽  
Urban Areas ◽  
World View ◽  
Urban Expansion ◽  
Land Development ◽  
Water Bodies ◽  
Pollution Level ◽  
Area Index ◽  
Land Cover Types

In 21st century, cities outpaced in size and also in density due to development of economic sector. Consequently, the wide spread expansion of urban areas is resulting in the loss of productive green cover and water bodies. Therefore, realizing this alarming situation, the present study is aimed to investigate and evaluate the pattern of urban expansion by considering two major land cover types (i) built-up area (ii) other classes (vegetation, waterbody, soil etc.) during the last six years (2015-2020). For this study Sentinel imagery was acquired from USGS Earth Explorer, while Modis Terra images were acquired from World View NASA. New built-up area index (NBUI), normalized difference vegetation index (NDVI), worldview water index (WV-WI) and land surface temperature (LST) were calculated in order to analyze variations in Lahore’s major land cover types and its varying temperature patterns. Spatial analysis presented the obvious impacts of land development on Lahore. NBUI indicated that the built-up area has increased drastically from 34.0% in 2015 to 84.2% in 2020; NDVI analysis depicted a decline from 0.76% to 0.73%, in the green spaces of Lahore during the study period; WV-WI portrayed inconsistent values of water bodies, a gift of massive rise in the built-up area in Lahore. LST results presented that the temperature was 42.21°C in 2015, which simultaneously increased and recorded at 49.51°C in 2020. The increase in LST exhibited the alarming situation for urban environment and can become threat to increase the air pollution level in Lahore. Therefore, this study will serve as a snapshot for policy makers to control the menace of unplanned urbanization by formulating stringent policies to protect environment.

scholarly journals An estimation of the evapotranspiration of typical steppe areas using Landsat images and the METRIC model

2021 ◽  
Author(s):  
Jun Wang ◽  
Heping Li ◽  
Haiyuan Lu
Keyword(s):  
Remote Sensing ◽  
Land Cover ◽  
Relative Error ◽  
Landsat Images ◽  
Area Index ◽  
Land Cover Types ◽  
Vapor Flux ◽  
Typical Steppe ◽  
Silage Maize ◽  
Metric Model

Abstract Remote sensing excels in estimating regional evapotranspiration (ET). However, most remote sensing energy balance models require researchers to subjectively extract the characteristic parameters of the dry and wet limits of the underlying surfaces. The regional ET accuracy is affected by wrong determined ideal pixels. This study used Landsat images and the METRIC model to evaluate the effects of different dry and wet pixel combinations on the ET in the typical steppe areas. The ET spatiotemporal changes of the different land cover types were discussed. The results show that the surface temperature and leaf area index could determine the dry and wet limits recognition schemes in grassland areas. The water vapor flux data of an eddy covariance system verified that the relative error between the ETd,METRIC and ETd,GES of eight DOYs (day of the year) was 18.8% on average. The ETMETRIC values of the crop growth season and the ETIMS of eight silage maize irrigation monitoring stations were found to have a relative error of 11.1% on average. The spatial distribution of the ET of the different land cover types in the study area was as follows: ETwater &gt; ETarable land &gt; ETforest land &gt; ETunutilized land &gt; ETgrassland &gt; ETurban land.

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