One of today's most important environmental problems is air pollution augmentation. Air pollution is getting worse over time and hurts human health. For the current study, various polar orbiting satellites were utilized to collect data on PM2.5, SO2, AOD, CO, and ozone over Pakistan between January 2005 and December 2021. According to the spatial distribution results, these characteristics have high values throughout central Punjab, western Baluchistan, central Sindh, and Khyber Pakhtunkhwa. The seasonal variation in PM2.5, SO2, AOD, CO, and ozone was calculated using monthly data. The greatest value for PM2 5 is 8.7 X 10-8 kg/m3 during the monsoon season, while the highest value for SO2 is 1.4 X 10-5 kg/m2 during the winter. Over Punjab, Sindh, Baluchistan, KPK, and Gilgit, AOD was between 0.7 and > 1.0, CO was 127.2 ppb, and ozone was 330.7 DU. Furthermore, we create correlation maps of AOD, CO, SO2, PM2.5, and ozone and evaluate their relationship of high and low values across Pakistan. We looked into the 0.99 correlation between AOD and PM2.5, the strongest ever recorded. Despite this, we look at time series graphs to show the rising and falling pattern of these parameters from January 2005 to December 2021. We also used tables to determine the relative change in Multan, Lahore, Karachi, Peshawar, Quetta, Rawalpindi, Faisalabad, Hyderabad, Gujranwala, and Abbottabad in Pakistan from January 2005 to December 2021.
The aboveground net primary productivity (ANPP) of bofedales is one of the most important indicators for the provision of ecosystem services in the high Andean areas. In the case of bofedales, the evaluation of the ANPP supply capacity as a service on a spatial and temporal scale through remote sensing has been little addressed. The capacity, intra and interannual, to provide the ANPP of the high Andean wetlands was quantified at a spatial and temporal level through remote sensing. The normalized difference vegetation index (NDVI) of the MODIS sensor was used according to the Monteith model (1972), product of the incident photosynthetically active radiation, fraction of the absorbed radiation, and the efficiency of using the radiation of the calibrated vegetation with dry matter sampling in the field. Results show an ANPP prediction R 2 of 0.52 (p < 0.05), with no significant spatial difference between field samples. When applying the model, the intra-annual temporary ANPP supply capacity presents a maximum average of 160.54 kg DM·ha -1·month -1 in the rainy season (December-May) and a maximum average of 81.17 kg DM·ha -1·month in the dry season (June-October). In 2003-2020, the interannual temporary capacity presented values of 1100-1700 kg DM·ha -1·year -1. This makes it possible not to affect the sustainability of the wetlands and prevent their depletion and degradation. Understanding the ANPP supply capacity of bofedales can favour the efficient use of the resource and indirectly benefit its conservation.
The chlorophyll-a (chl) abundances on the Fisheries Management Area of Indonesia Republic (WPP-RI 572), as fishery resources over the western coast of Sumatera (WSC) and Sunda Strait, were examined in this study. The extensive investigation on the mechanism ocean dynamics on chl variability along WSC was observed by using remotely sensed data on the surface. The spatial analysis was conducted using the Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua Ocean colour data for a period of January 2003 to December 2015. On seasonal time scale, the surface chlorophyll-a (schl) concentration in the southern tip of Sumatra is higher than the schl in the northern tip of Sumatra. The obtained results showed that the schl concentration in the southern tip of Sumatra increases (decreases) during the southeast (northwest) monsoons. Interestingly, its interactions with the southeast monsoon wind result in intensified coastal upwelling along the monsoon trough in July – August. It triggered a large bloom of the schl concentration from the upwelling region of southern tip Sumatra. Moreover, the schl in the center region followed the peak of the equatorial wind during the period transition in the Indian Ocean which is controlling the dynamics ocean such as upwelling event. Meanwhile, the opposite situation of the schl concentration observed low along the western coast of Sumatra during the northwest monsoon. At the same time, strong upwelling observed at the northern tip of Sumatra was associated with intense cooling on the sea surface temperature. It triggered a large bloom of high schl water from the upwelling region of northern Sumatra Island.
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Evapotranspiration (ET) is one of the key components of the hydrological cycle, and its accurate estimation is very important in agricultural usages. In this study, actual daily ET (ETa) from the Surface Energy Balance Algorithm for Land (SEBAL) and Mapping Evapotranspiration with Internalized Calibration/Earth Engine Evapotranspiration Flux (EEFLux) algorithms were used to compare the relative performance of the algorithms for the Landsat 8 images during the maize growth period. The results indicated that ETa was low at the beginning of the growing season and then came up to the middle of the growing season and then decreased due to decreasing temperature as well as changes in maize cover. The EEFLux algorithm has estimated about 7.71% of daily ET more than the SEBAL algorithm at the Arak maize farm. The results of performance evaluation showed that root mean squared error (RMSE), Nash–Sutclife coefficient of efficiency (NSE), percent bias error (PBIAS), and coefficient of determination (R2 ) criteria were obtained 0.711, 0.807, 7.398, and 0.885, respectively, based on the EEFLux algorithm and for SEBAL algorithm were equal to 1.046, 0.582, 15.080, and 0.793, respectively. According to the Taylor diagrams and observed data (lysimeter data), the EEFLux algorithm was closer to measured ETa values and had a higher correlation and a less standard deviation than the SEBAL algorithm. Therefore, the EEFLux algorithm had better estimation than the SEBAL algorithm.
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This paper presents the first results of a new way of using MODIS (Moderate Resolution Imaging Spectroradiometer) sensor data to visualize phytopigment inconstancy in the near-surface layer of water basins. Other sensors of this class alike, the MODIS spectral resolution is too low to reproduce the minimums of reflectance Rrs caused by phytopigments in water. However, MODIS is remarkable for the presence of a channel at 469 nm combined with channels at 412, 443, 488, 531, 547, and 555 nm. This makes it possible to distinguish the spectral limits of preferential light absorption by chlorophyll a (412-469 nm) and by accessory pigments (469-555 nm). These capabilities were realized thanks to spectral pixel indexation (SPI) of MODIS images of the sea surface. The SPI boils down to the fact that a user determines the presence of pigment minima in spectra of every image pixel, finds the sum of the wavelengths of these minima as a WRM code and assigns it to the image pixel as one of its attributes. WRM code = 100 is assigned to pixels free of the minima. Such indexation makes it possible to examine the inconstancy of phytopigments on the background of aquatic environment variability. Application of SPI approach to MODIS images of the Gulf of Mexico and the Baltic Sea made it possible to reveal new patterns of phytopigment dynamics during HABs events.
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Anthropogenic interventions have altered the natural environment and afected many of its physical, chemical, and biological characteristics. Changes in land use-land cover (LULC) are one of the main drivers that alter the hydrologic cycle and cause signifcant impacts on local, regional, and even the global climate system. It is now widely recognised and accepted that climate change is one of the gravest problems that our planet Earth is facing at present. This study analyses the impact of LULC dynamics on the spatial and temporal variation of land surface temperature (LST) in an inter-state river basin, which also happens to be the largest river basin in the state of Kerala, India, viz. the Bharathapuzha river basin, during the period 1990–2017. LST time-series analysis (derived from Landsat) revealed that 98% of the river basin experienced LST less than 298 K in January 1990. Over time, along with changes in LULC, LST also increased; in 2017, about 7.82% of the river basin experienced LST greater than 312 K. A notable change in LULC that occurred during this period was the drastic increase in areas with high albedo. The seasonal curves of LST derived from MODIS data are strong evidence of the devastating impacts of change in LULC on LST and, in turn, on climate change. The major spatial and temporal components of change in LST in the study region were identifed by principal component analysis (PCA). The results of this spatiotemporal analysis spread over a period of 28 years can be used for formulating sustainable development policies and mitigation strategies against extreme climatic events in the river basin.
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Chlorophyll-a (Chl-a) concentration is an important issue in ocean ecosystem management and research. This study investigates seasonal and annual variability in Chl-a and its relationship with sea surface temperature (SST) and river discharge in the shelf region of the Northern Bay of Bengal (BoB), as well as validates satellite data against in-situ data. Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua satellite data on Chl-a concentration and SST from 2002–2018 were used in this study. River discharge data were obtained from the Bangladesh Water Development Board (BWDB). The annual Chl-a concentration ranged from 2.08 to 2.94 mg m−3, with an average of 2.43 ± 0.24 mg m−3. The Chl-a concentration was found higher (2.21 ± 0.56 mg m−3) during the northeast monsoon (October–February) and lower (1.81 ± 1.14 mg m−3) during the pre-monsoon season (March–May). The study revealed a declining trend in Chl-a concentration from 2002 to 2018, and the rate of change was −0.0183 mg m−3 year−1. Chl-a concentration showed a weak inverse relationship with SST, both annually and seasonally, especially in the pre-monsoon season. River discharge masked the effect of SST on Chl-a variability during the southwest and northeast monsoon. A reasonable correlation (r = 0.78) was found between the MODIS-Aqua data and in-situ Chl-a observations.
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The Brazil-Malvinas Confluence Zone (BMCZ) is characterized by high environmental variation, which could be reflected in several optical types of water, from one containing only phytoplankton and sea water to other optically more complex. In this paper, we analyze the spatio-temporal variability of the Chlorophyll-a detected by the ocean color sensor (CHLAsat) in BMCZ in order to understand its environmental variability. We use the MODIS-Aqua CHLAsat monthly composites imagery from 2002 to 2015, and applied two statistical methods: the correlogram-based robust periodogram to identify, over a broad spectrum of temporal, the most significant periodicities, and the pixel gradient distribution to study the spatial-temporal gradients within the BMCZ and variations over the continental shelf and coastal waters. Our results point out to the predominance of the annual cycle over most of the investigated area, although an area from latitude 37°S in direction NE, alongshore of Uruguay to Brazil, evidences interannual periodicities, possibly related to variations in the discharge of the Rio de la Plata associated with the El Niño phenomena. The ocean color spectroradiometric signature in terms of pixel gradient presents a relatively high variability (∼0.0 to 0.65 mg m−3); in particular the high values of the pixel gradient correspond to saline front of the estuarine system of Rio de la Plata, and to the strip of the platform that extends along the isobaths of 80 m (coast of Uruguay), especially in the center and south of the study area.
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We examine the narrowband shortwave minima (NSM) of multispectral reflectance as indication of mesoscale algal blooms. They are frequent in the Brazil-Malvinas confluence zone (BMCZ) where our testing site (TS) belongs. Its MODIS A images of December 2008 and 2014 were the source of initial data. Classification of reflectance spectra in these images revealed that the TS look from space was determined by the most populated cluster of pixels having the only NSM at 443 nm. We divided this cluster into sub-clusters by maximum wavelengths λmax from 412 to 555 nm and retrieved the estimates of λmax (proxy for abundance of colored dissolved organic matter (CDOM)), chl_a (MODIS chlorophyll), Rrs (555) (turbidity proxy), and CALH (NSM-based chlorophyll) on a pixel-by-pixel basis. This allowed us to demonstrate: (1) the NSM magnitude at 443 nm peaked in mesoscale structures, (2) CALH was consistent with chlorophyll in the BMCZ waters samples, (3) positive linear correlation of Rrs (555) and CALH was characteristic of the TS waters at any λmax, (4) the MODIS chl_a was overestimated when λmax > 488 nm, (5) localization and outlines of mesoscale structures agreed well in the fields of pairs Rrs (555) – CALH and λmax – chl_a, but not in the CALH – chl_a pair. The NSM-based chlorophyll CALH outperformed the standard chl_a determinations in exactness because the CALH is insensitive to CDOM. This is advantageous when studying the Case 1 waters of intensive mesoscale variability where chlorophyll co-exists with the CDOM from eddy-induced blooms.
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From a data set of observations of Suspended Particulate Matter (SPM) concentration, Turbidity in Formazin Turbidity Unit (FTU) and fluorescence-derived chlorophyll-a at a mooring station in Liverpool Bay, in the Irish Sea, we investigate the seasonal variation of the SPM: Turbidity ratio. This ratio changes from a value of around 1 in winter (minimum in January-February) to 2 in summer (maximum in May-June). This seasonal change can be understood in terms of the cycle of turbulence and of the phytoplankton population that affects the nature, shape and size of the particles responsible for the Turbidity. The data suggest a direct effect of phytoplankton on the SPM: Turbidity ratio during the spring bloom occurring in April and May and a delayed effect, likely due to aggregation of particles, in July and August. Based on the hypothesis that only SPM concentration varies, but not the mass-specific backscattering coefficient of particles bbp *, semi-analytical algorithms aiming at retrieving SPM from satellite radiance ignore the seasonal variability of bbp * which is likely to be inversely correlated to the SPM: Turbidity ratio. A simple sinusoidal modulation of the relationship between Turbidity and SPM with time helps to correct this effect at the location of the mooring. Without applying a seasonal modulation to bbp *, there is an underestimation of SPM in summer by the Ifremer semi-analytical algorithm (Gohin et al., 2015) we tested. SPM derived from this algorithm, as expected from any semi-analytical algorithm, appears to be more related to in situ Turbidity than to in situ SPM throughout the year.
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Numerous ecological problems of continental shelf ecosystems require a refined knowledge of the evolution of suspended sediment concentrations (SSC). The present investigation focuses on the spatial and temporal variabilities of near-surface SSC in coastal waters of the English Channel (western Europe) by exploiting numerical predictions from the Regional Ocean Modeling System ROMS. Extending previous investigations of ROMS performances in the Channel, this analysis refines, with increased spatial and temporal resolutions, the characterization of near-surface SSC patterns revealing areas where concentrations are highly correlated with evolutions of tides and waves. Significant tidal modulations of near-surface concentrations are thus found in the eastern English Channel and the French Dover Strait while a pronounced influence of waves is exhibited in the Channel Islands Gulf. Coastal waters present furthermore strong SSC temporal variations, particularly noticeable during storm events of autumn and winter, with maximum near-surface concentrations exceeding 40 mg l−1 and increase by a factor from 10 to 18 in comparison with time-averaged concentrations. This temporal variability strongly depends on the granulometric distribution of suspended sediments characterized by local bimodal contributions of silts and sands off coastal irregularities of the Isle of Wight, the Cotentin Peninsula and the southern Dover Strait.
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The Levantine basin in the Eastern Mediterranean Sea is subject to spatial and seasonal variations in primary production and physical-chemical properties both on a short and long-term basis. In this study, the monthly means of daily MODIS product images were averaged between 2002 and 2015, and used to characterize the phytoplankton blooms in different bioregions of the Levantine basin. The selected products were the sea surface temperature (SST), the chlorophyll-a concentration (Chl-a), the diffuse attenuation coefficient for downwelling irradiance at 490 nm (Kd_490) and the colored dissolved organic matter index (CDOM_index). Our results showed that phytoplankton blooms were spatially and temporally variable. They occurred in late autumn at the Nile Delta, in early spring and late summer at the eastern coastline, and in spring at the northeastern coastline. The northern coastline and the open water had a common bloom occurring in winter. The Nile Delta was found to be the most productive area of the Levantine basin showing high Chl-a. Kd_490 and Chl-a present a parallel co-variation indicating a dominance of Case 1 waters in the Levantine basin. The CDOM_index shows a phase shift with the Chl-a fluctuation. A strong inverse correlation was observed between both Chl-a and CDOM_index with SST, connoting an indirect relation represented by a depression of CDOM in summer by photobleaching, and a suppression of the chlorophyll-a concentration due to water stratification, together with nutrient stress. An overestimation of the Chl-a values had been signaled by the use of the CDOM_index, suggesting a correction plan in a latter study.
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We propose a new approach to indication of algal blooms. It stems from analysis of the multispectral satellite reflectance Rrs of areas where blooms were documented during recent decades. We found that spectra of algal blooms exhibit minima at wavelengths of channels of Moderate Resolution Imaging Spectroradiometer (MODIS) λ = 443 and λ = 488 nm (Baltic, Black, and Caspian seas), λ = 443 nm (Southwest Tropical Pacific (SWTP)), and λ = 443 nm and λ = 469 nm (Patagonian Continental Shelf (PCS)), attributable to absorption bands of chlorophyll a and accessory pigments. We quantified the minima using indices D1 = Rrs(443) − Rrs (412) and D2 = Rrs (488) − Rrs (469) and proved their diagnostic potential by comparing their distributions to that of Rrs (555). Linear dependence of D1 upon chlorophyll a was found from MODIS data for the bloom of Nodularia spumigena. Time dependences of D1 and D2 point to the latter as a probable remote forerunner of cyanobacterial blooms. In the PCS, D1 and D2 proved to be too simplistic owing to diversity of spectral shapes at λ < 550 nm. Cluster analysis revealed close linkage of the latter and local oceanological conditions. Our findings bear witness to the diagnostic potential of the indices by virtue of their direct relation to pigment absorption and because the broadband background reflectance changes reduce when calculating the indices as a difference of spectrally close reflectances. Further studies are needed to convert the indices to band-difference algorithms for retrieving the bio-optical characteristics of algal blooms.
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Satellite Moderate Resolution Imaging Spectroradiometer (MODIS) data of water leaving radiance of 859 nm with a spatial resolution of 250 m were used to investigate the impact of atmospheric gravity waves (AGWs), which manifested as stripes in clouds and on the sea surface. On the basis of an evaluation of the characteristics of AGWs and sea depth, it was shown that the surface stripes, or surface waves (SWs) were imprints of AGWs. Crests of SWs were like prolongations of cloud stripes on the combined radiance images testifying that SWs were shifted by minus a quarter of the period relative to AGWs.
W artykule przedstawiono propozycję wykorzystania satelitarnych danych pozyskanych przez spektroradiometr MODIS do wyznaczania obszarów ograniczonej widzialności. Autorzy skupili swoją uwagę na dwóch obiektach meteorologicznych: mgłach i niskich chmurach warstwowych (Stratus). Wysoka rozdzielczość przestrzenna i spektralna danych pozwala na ocenę dominujących procesów zachodzących w dolnej troposferze, wpływających na ograniczenie widzialności. Znaczenie wykorzystania wielospektralnych danych satelitarnych wzrasta w przypadku analizy warunków na obszarach o niewystarczającej gęstości sieci bezpośrednich pomiarów meteorologicznych. Wyniki analiz obrazów wykonanych w pojedynczych zakresach spektralnych, produktów różnicowych i kompozycji barwnych mogą być wykorzystywane w systemach monitorowania i ostrzegania o warunkach drogowych.
EN
The paper presents a proposal of application of satellite data acquired by means of the MODIS spectroradiometer to determination of areas of limited visibility. The authors focused on two meteorological objects: fogs and low layer clouds (Stratus). High spatial and spectral resolution of the data enables to assess the prevailing p rocesses in the lower troposphere that cause limited visibility. The significance of the multispectral satellite data application increases in cases of weather conditions analyses for areas of sparse networks of direct meteorological measurements. The results of analyses of single spectral channels images, differential products and color compositions may be used in road conditions monitoring and warning systems.
Celem niniejszej pracy było porównanie dat początku okresu wegetacyjnego (OW) na obszarze Polski w okresie 2001–2010, które wyznaczono na podstawie dwóch niezależnych metod. Do wyznaczania dat metodą Gumińskiego wykorzystano średnie miesięczne wartości temperatury powietrza z punktów gridowych rozmieszczonych na terenie kraju. Natomiast do określenia dat początku OW metodą teledetekcji satelitarnej wykorzystano dane pochodzące z NASA LP DAAC, które były wynikiem pomiarów wykonywanych przez wielospektralny skaner MODIS umieszczony na satelitach Terra i Aqua. Wykazana została znaczna zgodność średnich terminów początku OW w Polsce wyznaczonych tymi dwoma metodami, co może sugerować istotny wpływ czynnika termicznego na wzrost aktywności fotosyntetycznej roślinności po okresie zimowym. Obydwie metody potwierdziły, że przeciętnie najwcześniej początek OW występuje w południowo-zachodniej części kraju, natomiast najpóźniej w Polsce Północnej i na obszarach górskich.
EN
The aim of the paper is to compare the dates of the onset of the growing season in Poland in the period 2001–2010, which were determined on the basis of two independent methods. The dates determined by Gumiński method based on gridded monthly mean air temperature over Poland area. In turn, satellite data extracted from NASA LP DAAC product, which were the result of measurements performed with multispectral scanner (MODIS) on the Terra and Aqua satellites. It was demonstrated that the average dates of the onset of the growing season in Poland determined by two methods did not differ significantly. It may suggest a significant impact of thermal factor on the increase in the photosynthetic activity of vegetation after the winter months. Both methods confirmed that the earliest average dates of the onset of the growing season occur in the southwestern part of the country, and the latest in northern Poland and in the mountain areas.
The paper presents the capability of applying selected modern remote sensing methods based on commonly available high spatial resolution MODIS images to fog and low layer clouds detection. Single spectral channel images, differential images and selected color compositions are analyzed for distinguishing the areas of the phenomena occurrence. Their internal structure and fog/cloud particles properties are assessed using brightness temperature and reflectance diagrams.
PL
Artykuł przedstawia możliwości zastosowania wybranych współczesnych metod teledetekcyjnych opartych na powszechnie dostępnych zobrazowaniach MODIS o wysokiej rozdzielczości do wykrywania obszarów mgieł i niskich chmur warstwowych. Do wykrywania obszarów występowania tych zjawisk wykorzystywane są wyniki analiz zobrazowań w pojedynczych kanałach spektralnych, zobrazowania różnicowe oraz wybrane kompozycje barwne. Wewnętrzna struktura zjawisk i własności cząstek mgły/chmur warstwowych analizowane są na podstawie diagramów temperatury radiacyjnej i odbiciowości.
In the paper, the integrated method is presented, which combine the static approach with the dynamic one. Firstly, the static model, which describes the terrain susceptibility, is develop on the base of the fire statistics and the environmental information such as: vegetation type, slope and aspect of the terrain. In order to estimate the static index the environmental modeling implemented in GIS was used. Later, the dynamic method was created on the base of the MODIS satellite images. The most important and changeable variables were estimated from the images: surface temperature, water vapor and dryness of the vegetation. The dynamic index which describes the current fire situation was obtained. Finally, two indexes integrated into one, which combine the current fire risk with the terrain susceptibility.
W artykule przedstawiono ocenę możliwości zastosowania teledetekcji satelitarnej do monitorowania wegetacji rzepaku ozimego na przykładzie dwóch wybranych punktów z obszaru Lubelszczyzny. Do badań wykorzystano pięć wskaźników wegetacyjnych (NDVI, EVI, LAI, fPAR i GPP), których wartości pochodziły z pomiarów wykonywanych w okresie 2000–2012 przez satelitę środowiskowego Terra. Z kolei dane dotyczące wysokości roślin rzepaku przed zimą i dat początku kwitnienia tej rośliny odnosiły się do dwóch obszarów (w rejonie Bezka i Ciciboru Dużego), na których znajdowały się pola doświadczalne Centralnego Ośrodka Badania Odmian Roślin Uprawnych (COBORU). Uzyskane wyniki wykazały możliwość wykorzystania danych satelitarnych do prognozowania ze znaczną dokładnością obu analizowanych cech rzepaku ozimego. Ponadto na podstawie wskaźników wegetacyjnych stwierdzono, że wzrost i rozwój tej rośliny w znacznym stopniu zależał od przebiegu warunków atmosferycznych.
EN
This paper presents an assessment of the applicability of satellite remote sensing data to monitor the growth and development of winter oilseed rape in the Lublin region. The study used five vegetation indices (NDVI, EVI, LAI, fPAR and GPP), whose values were derived from Terra environmental satellite and related to the period between 2000 and 2012. Values of the oilseed rape height before winter and the onset of flowering stage based on fi eld observations from the Experimental Stations for Cultivar Testing (COBORU) in Bezek and Cicibór Duży. The results showed the possibility of using satellite data to predict with a fairly high degree of accuracy both analyzed characteristics of winter oilseed rape. Moreover, based on vegetation indices it has been confirmed that the growth and development of the winter oilseed rape are highly dependent on the course of weather conditions.
Dokonano analizy porównawczej powierzchniowej miejskiej wyspy ciepła (PMWC) trzech polskich miast: Warszawy, Krakowa i Wrocławia. Jako termin analiz wybrano okres fali upałów na terenie Polski w sierpniu 2013 roku. Wykorzystano termalne zobrazowania satelitarne powierzchni Ziemi dla pory dziennej (zarejestrowane 8 sierpnia 2013 o godzinie 11:40 czasu lokalnego) oraz dla pory nocnej (zarejestrowane 5 sierpnia 2013 o 22:20 czasu lokalnego). Zakres prac dotyczył porównania dwóch rodzajów PMWC - powierzchniowo uśrednionej oraz bezwzględnej. Uśredniona powierzchniowo PMWC w ciągu dnia w Krakowie wyniosła 2,4°C (w nocy 1,6°C), w Warszawie 2,2°C w dzień (2,1°C w nocy), we Wrocławiu w dzień 0,8°C (0,9t w nocy). Warszawska PMWC miała największą powierzchnię zarówno w dzień, jak i nocy. W dzień bezwzględna PMWC w Warszawie wyniosła 14,6°C (w nocy 6,3°C), w Krakowie 11,8°C (w nocy 8,5°C), we Wrocławiu 10,1°C (w nocy 7,7°C). Ponadto dokonano identyfikacji obszarów o największych różnicach temperatur powierzchni miedzy porą dzienną a nocną.
EN
Thermal satellite remote sensing data obtained by the MODIS instrument (Moderate Resolution Imaging Spectroradiometer) have been applied in an inter-comparison study of surface urban heat island (SUHI) phenomena in three cities in Poland (Warsaw, Cracow, Wroclaw) during an extreme heat wave in August 2013. Two satellite images were analyzed for day and night case comparison. One was acquired on 8 August 2013 at 11:40 local time (the day case), the second on 5 August 2013 at 22:20 local time (for the night case). Two types of SUHI were analyzed - an absolute SUHI and a spatially averaged SUHI. The performed study shows that Cracow's spatially averaged SUHI has the highest magnitude in the day (2.4°C), Warsaw's SUHI has the biggest spatial extent during day and night, Wroclaw's SUHI is the smallest in terms of spatial extent and magnitude. In Warsaw, absolute SUHI was 14.6°C (at night 6.3°C), in Cracow 11.8'C (at night 8.5°C), in Wroclaw 10.1°C (at night 7.7°C). Also, areas of the cities with the highest diurnal thermal differences were identified.
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