Microsoft Word - 23-Bio_33990 1038 Original Article Biosci. J., Uberlândia, v. 33, n. 5, p. 1038-1047, Sept./Oct. 2017 SYNOPTIC EVENTS ASSOCIATED WITH THE LAND SURFACE TEMPERATURE IN RIO DE JANEIRO EVENTOS SINÓPTICOS ASSOCIADOS DA TEMPERATURA SUPERFÍCIE DA TERRA NO RIO DE JANEIRO Rafael Coll DELGADO1; José Francisco de OLIVEIRA-JÚNIOR2; Givanildo GOIS3; Rafael de Ávila RODRIGUES4; Paulo Eduardo TEODORO5* 1. Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ, Brasil; 2. Universidade Federal de Alagoas, Maceió, AL, Brasil. 3. Universidade Federal Fluminense, Volta Redonda, RJ, Brasil; 4. Universidade Federal de Goiás, Catalão, GO, Brasil. 5. Universidade Federal de Mato Grosso do Sul, Chapadão do Sul, MS, Brasil. eduteodoro@hotmail.com ABSTRACT: This article aimed to evaluate land surface temperature using MOD11A2 (Terra satellite) with spatial resolution of one kilometre, compares its findings with land surface temperature data gathered by conventional meteorological stations, and, finally, investigates relations between land surface temperature and synoptic systems events that occurred in Rio de Janeiro State between January until December of 2009. The highest surface temperatures recorded by the MOD11A2 product, derived from the MODIS sensor, were found in the Metropolitana, Baixadas Litorâneas, Norte Fluminense and Noroeste Fluminense regions of Rio de Janeiro State and were recorded during the summer, winter and spring seasons. Autumn was the only exception, and this was due to the influence of the coastal environment. The following synoptic systems interfered with the estimated surface temperature produced by the MOD11A2 product for Rio de Janeiro State in 2009: the Madden Julian Oscillation and South Atlantic Convergence Zone in the summer; and Frontal Systems, the South Atlantic Convergence Zone, the Madden Julian Oscillation and the Upper Tropospheric Cyclonic Vortex in spring. The land use and occupation types with the highest surface temperature are: forest, urban area and pasture land in the summer; forest, urban area, agriculture and pasture land in autumn; and urban area and agriculture during spring. The MOD11A2 product showed a drastic decrease of the surface temperature for all land types during winter, especially for forested land. KEYWORDS: Southeast region. Remote sensing. Thermal field. Meteorological satellite. INTRODUCTION Worldwide urbanization and population growth, and the ways in which they have changed the use and occupation of land, are thought to be probable causes of global warming. These processes do not only alter the landscape: anthropic activities also contribute to greenhouse gas emissions (GGE) which affect global warming (SATTERTHWAITE, 2008). The urbanization process produces greater changes in land surface and atmospheric properties, such as the energy partitioning between urban and adjacent areas, thus creating a new urban climate (OKE et al., 1992). Changes to the land surface, such as urbanization, substitute natural surfaces for buildings, roads and streets, significantly increasing the level of soil waterproofing as well as altering its thermal properties (e.g. specific heat and thermal conductivity) and radioactivity (e.g albedo) (ANJOS et al., 2013). As a consequence, there have been an increasing number of floods as well as changes in radiation and energy surface balance. In the last few years, urbanized areas have seen an increase in concentrated heat (the phenomenon known as the urban heat island effect), linked to a rise in severe rainfall, and it is fast becoming a significant problem for affected populations and policy makers (RAMANATHAN; FENG, 2009). The process of urbanization alters the Surface Energy Balance (SEB), and does so as much for short as for long wavelength radiation emission. The thermal properties of the materials used in urban building and construction promote faster heat conduction than that of soil and vegetation in rural areas, thus contributing to increasing dissimilarity of temperature between urban and rural regions (FREITAS; DIAS, 2005). Surface temperature is directly influenced by climate variation, and precise evaluation is of great importance for research monitoring spatial dynamics such as urbanization processes, natural catastrophes or other landscape changes. The decrease of green areas creates changes in the local atmosphere, thus modifying patterns of temperature, rain, and wind direction and speed (KATO; YAMAGUCHI, 2005). When using the data gathered by the Thematic Mapper (TM) to study the influence of landscape change in Cruzeiro do Sul, in the Brazilian State of Acre, Delgado et al. (2012) found an increase in the number of anthropised areas between 2005 and 2010. These researchers also established another important result: they noted that Received: 16/04/16 Accepted: 05/12/16 1039 Synoptic events associated… DELGADO, R. C. et al. Biosci. J., Uberlândia, v. 33, n. 5, p. 1038-1047, Sept./Oct. 2017 areas transformed by human action had seen temperature increases, with values reaching 40°C and above, something which contributed to an increase in precipitation of 17.6 mm-1.year-1 (1971- 1990) and reached a maximum value of 30.5 mm- 1.year-1 between 1993 and 2002. Against that background, this article aimed to evaluate land surface temperature using MOD11A2 (Terra satellite) with spatial resolution of one kilometre, compares its findings with land surface temperature data gathered by conventional meteorological stations, and, finally, investigates relations between land surface temperature and synoptic systems events that occurred in Rio de Janeiro State between January until December of 2009. MATERIAL AND METHODS Characterization and location of the research area This research examined Rio de Janeiro State, which is located in the Southeast region of Brazil, in the country’s east coast, and between the meridians 40° 57’ 59” W and 44° 53’ 18” W, and parallels 20° 45’ 54” S e 23° 21’ 57” S (Figure 1). Rio de Janeiro State shares borders with Espírito Santo State in the northeast, with Minas Gerais State in the north and northwest, with São Paulo State in the southeast, and with the Atlantic Ocean in the south and east. The Conventional Meteorology Stations belong to the National Institute of Meteorology (INMET) and are spatially distributed so as to represent the physiographic conditions of the State. Rio de Janeiro State has a territorial area of 43,780.172 km², and a population of 15,993.583 in habitants. The state is geopolitically divided into 92 municipalities, which are grouped together into eight different meso-regions (subdivisions of Brazilian States): Norte Fluminense, Noroeste Fluminense, Serrana, Centro Sul Fluminense, Baixadas Litorâneas, Metropolitana, Médio Paraíba and Costa Verde (IBGE, 2013). Figure 1. Hypsometric map (m) obtained from SRTM. Mesoregion classification and the INMET conventional meteorological stations used in 2009 in Rio de Janeiro State. Air temperature data series (2009) We used 2009 daily time series data gathered from seventeen stations for a specific day of the year (astronomic day of the year) to evaluate the evolution of the air temperature recorded by the INMET Conventional Meteorological Stations. The analysis of maximum and minimum air temperature was conducted between January until December 2009. We then obtained the mean value representing the average time of the satellite passing over the state of Rio de Janeiro, which was at 10:30 Local Standard Time (LST). Images from the MOD11A2 MODIS product, with spatial resolution of 1km, were acquired for the same period. Analysis of land surface temperature recorded by MOD11A2 and SRTM In order to conduct this study, we used twelve monthly images (January until December 2009) gathered by the MOD11A2 MODIS product (Land Surface Temperature), onboard the Terra satellite. The product has 8-day data composed from the daily 1 Km resolution imagery These images were obtained from NASA (National Aeronautics and Space Administration), USGS (U.S. Geological 1040 Synoptic events associated… DELGADO, R. C. et al. Biosci. J., Uberlândia, v. 33, n. 5, p. 1038-1047, Sept./Oct. 2017 Survey) and EROS (Earth Resources Observation and Science Center) on the 8th September 2013. They can be found at the following web address: . The images are in the Hierarchical Data Format (HDF) and Sinusoidal projection. It was necessary to convert the HDF format into GEOTIFF and the Sinusoidal projection into UTM WGS 84 for the images to be processed by the ArcGis 10.2. To achieve this, we had to pre-process the images using the Modis Projection Tool (MRT) algorithm. The MRT is a software tool exclusively designed to work with MODIS images. When working with this software, we chose the ‘LST_Day_1km’ image, and also selected the geographic position and the UTMWGS84 projection parameter. The Tile (a subdivision of the available areas of MODIS Products) which includes Rio de Janeiro state was the H13V11 and H14V11, with a total of 24 images used to cover the period of 2009. The MOD11A2 product (Land Surface temperature – LST) is derived from the MODIS sensor, one of the best sensors for radiometric resolution in the collection 5 of the thermal band, with spatial resolution of 1 km. The sensor uses the LST algorithm, including the Day/Night LST algorithm (WAN, 2007), to produce data on land surface temperature. This algorithm was specifically developed for MODIS and produces daytime and night-time thermal images for the whole surface of the Earth. Daily periodicity is validated by the MAS (MODIS Airborne Simulator) images and by field measurements conducted between 1996 and 1998 (WAN et al., 1998). The MOD11 product incorporates, in its algorithm emission data, viewing angle (developed to correct atmospheric effects), information on the surface reflectivity, emission, absorption and atmospheric dispersion, as well as information on solar radiation on the day. The A2 product is a composition of eight days, produced after the daily data generated by the A1 product. We chose to use collection 5 as it has improved methodological capabilities when compared to collection 4 (WAN, 2007). A few data adjustments are necessary before applying the land surface temperature model. As they are pre-processed products, they are often available in a 16 bit format, so that in order to employ them they first need to be converted into their respective units. This was done by applying the ArcGIS 10.2 Spatial Analyst Tools – with a Raster Calculator in the Map Alebra toolset. Finally, in order to utilize the 16 bit MOD11A2 product, we also had to convert it to Kelvin (TK, K) (Equation 1). 0.02*NDTK = (1) ND is the Digital Number (MOD11A2) and 0.02 is the constant used in converting to Kelvin. After converting the MOD11A2 product to temperature values in Kelvin, we used the ArcGIS 10.2 software to work on the vector data, database, calculation of the surface temperature and map creation. We also used images generated by radar, which were obtained by the sensors aboard the Endeavour space shuttle, installed for the SRTM (Shuttle Radar Topography Mission) project. We used the ERDAS IMAGINE software to produce a mosaic of Rio de Janeiro State. The SRTM Elevation Digital Model, with 3 arc seconds (about 90 m spatial resolution) is available free from the American government (MIRANDA, 2013). We used the ArcsGIS 10.2 Geographically Weighted Regression tool for a multiple linear regression analysis of the independent variables (latitude, longitude and altitude) to enable to evaluate the dependable variable (the land surface temperature of the MOD11A2 product). The analysis employed the following equation: ii3i2i10iS εAltβLongβLatββT ++++= (2) In the above equation, TSi (K) is the land surface temperature; Lati (degrees and tenths) is the latitude; Longi (degrees and tenths) is the longitude; Alti (m) is the altitude; β0, β1, β2, β3 are the regression coefficients; and εi is the random error, independently assumed and with normal distribution, zero mean and constant variation. We considered the negative sign of longitude and latitude to represent west from the Greenwich and South Hemisphere. Statistical methods We have used statistical methods available in the current literature to evaluate the performance of the methodology applied in our research. They are based on comparative analyses of the proposed methodology and the data gathered from the Automatic Meteorological Station. We applied the determination coefficient (r2), followed by the estimated mean standard error (SEM, ºC) (ALLEN et al., 1989), mean bias (MB ºC) and index of agreement (d) proposed by Willmott et al. (1985). Land use and occupation During the seasonal evaluation of the land surface temperature, we tried to verify the relationship between land temperature and the different forms of soil usage found in Rio de Janeiro State by using the data supplied by the 1041 Synoptic events associated… DELGADO, R. C. et al. Biosci. J., Uberlândia, v. 33, n. 5, p. 1038-1047, Sept./Oct. 2017 Environmental State Institute (Instituto Estadual do Ambiente – INEA) website (web address: http://www.inea.rj.gov.br/basetematica_estadoambie nte/). We selected four types of land use in the ArcGIS 10.2 software: forest, pasture, urban area and agriculture. For this purpose, we used the spatial analysis and data extraction tools. We then analysed the seasonal variations for the different classes and the information obtained for land surface temperature. Afterwards, we conducted an exploratory analysis of the data by using box-plots, which allowed us to visualise the location, dispersion, symmetry, outlier barriers as well as the outliers themselves, independently from the form of the distribution of the dataset. Description of the meteorological events between January until December 2009 Based on the data gathered from the CLIMANÁLISE bulletins, we conducted a study of the main synoptic systems’ events that occurred in Rio de Janeiro State in 2009 (CPTEC, 2013). We then described the synoptic systems according to their influence on the variability of the land surface temperature, data which was gathered from the MOD11A2 during the days the Terra satellite passed over during the seasonal scale period. RESULTS AND DISCUSSION Algorithm test The dispersion in the surface temperature estimates was high for every month of the year, as indicated by values for the determination coefficient (r2) of between 0.11 (October) to 0.52 (November) (Table 1). High dispersions in values suggest a significant contribution of non systematic errors (WILLMONTT, 1981). Highest dispersions in the estimates (higher than r2) were observed during the change between winter (August) and spring (September and October) with com r2 < 0.19, and the smallest dispersions (r2 > 0.49) during autumn (April and May) and in November. Even though the dispersion in the estimates was high, as indicated by the low r2, the standard error of the estimate was below 3.8K (October), representing less than 1.5% of the average value of the estimated surface temperature. In absolute terms, the months of January and February (summer months) and October (spring) had the highest value standard error of the estimate (> 3.1 K), whereas we recorded the lowest values (< 2.2 K) during the transition between autumn and winter (April and May) and in winter (June and July). The mean (Standard Error of the Estimate/average) of January and October presented the highest errors, 1.15 and 1.29% respectively, and the lowest errors (< 0.76%) occurred during the autumn months and in June. The average tendency was towards over estimation (Figure 3), with the exception of July, October and December, where there was an overestimation for values lower than 307K (December), 296 K (July) and 303 K (October) and underestimation for higher values. Table 1. Statistical analysis of the land surface temperature (K) and the MOD11A2 product data for the period of January to December 2009 in Rio de Janeiro State. Month EPE (K) VM a (K) b r2 d Jan 3.44 0.1937 16.28 0.957 0.28 0,49 Feb 3.11 0.0554 -50.25 1.170 0.29 0,60 Mar 2.83 0.1741 70.17 0.777 0.27 0,51 Apr 1.73 0.0680 81.27 0.737 0.50 0,77 May 1.83 0.1925 60.37 0.801 0.49 0,58 Jun 2.24 0.0639 25.39 0.917 0.38 0,73 Jul 1.75 0.0234 148.86 0.498 0.35 0,93 Agu 2.48 0.1899 176.22 0.415 0.16 0,52 Sep 2.70 0.1499 78.15 0.747 0.19 0,49 Oct 3.83 0.1706 186.57 0.383 0.11 0,55 Nov 2.33 0.3551 -107.26 1.377 0.52 0,38 Dec 2.48 0.1816 163.17 0.468 0.27 0,64 Values for the month of July showed high agreement between the estimates and the observed data, confirmed by the Willmott coefficient of agreement (d) of 0.93; followed by April with 0.77 1042 Synoptic events associated… DELGADO, R. C. et al. Biosci. J., Uberlândia, v. 33, n. 5, p. 1038-1047, Sept./Oct. 2017 and June with 0.73. We observed the lowest agreement values (< 0.49) during January and in spring (September and November). The lower levels of precision and agreement of the estimates in the spring and summer months are due to the highest measures of rainfall being recorded during this period in Rio de Janeiro State. Rainfall during these seasons is highly variable spatially and in terms of intensity due to the tropical convection system that intensifies the atmospheric systems related to the rain (e.g. the Frontal Systems and the South Atlantic Convergence Zone) and to the mesoscale connective systems (ANDRÉ et al., 2008). On the other hand, during the autumn and winter months, the total amount of rainfall is less than that in summer and spring and is mainly related to frontal systems, which are less spatially variable. Although the values for r² for January, February, May and June were lower than 0.38 and the standard error of the estimate was higher than 1.8 K, the angular regression coefficient (b) for the observed data and estimated data was close to 1 (0.92 in June and 1.17 in February). This result indicates the scale of the contribution of the proportional systematic error in the estimates (WILLMOTT, 1985), seen in the regression lines found approximately parallel to the line 1:1 (Figure 2 – Summer and Winter). The autumn months (March and May) and the spring months (September and November) showed similar results, in other words, a significant contribution due to proportional systematic error. However, the difference between the ideal value was higher: 0.747. Acesso em mar.2013. INEA – Instituto Estadual do Ambiente. Base Temática. Disponível em: < http://www.inea.rj.gov.br/basetematica_estadoambiente/>. Acesso em jun. 2013. KATO, S.; YAMAGUCHI, Y. Analysis of urban heat-island effect using ASTER and ETM+ Data: Separation of anthropogenic heat discharge and natural heat radiation from sensible heat flux. Remote Sensing of Environment, Salt Lake City, v. 99, p. 44-54, 2005. https://doi.org/10.1016/j.rse.2005.04.026 LYRA, G. B.; SANTOS, M. J.; SOUZA, J. L.; LYRA, G. 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