Abstract

Iran Land surface temperature mapping using Classification-based emissivity

Mehdi Akhoondzadeh
Tehran University, Iran
Email: mehdi_akhoondzadeh@yahoo.com

Mohammad Reza Saradjian
Tehran University, Iran
Email: sarajian@ut.ac.ir


Abstract :
This paper presents application of the Earth Observing System (EOS) Moderate Resolution Imaging Spectroradiometer (MODIS) thermal infrared bands for Land Surface Temperature (LST) retrieval. A brief summary of the Generalized split-window algorithm discuss and then LST map of Iran was calculated from Terra-MODIS 1km resolution images.

LST is a good indicator of the energy balance at the surface because it is one of the key parameters in the physics of land-surface processes. It combines the results of surface-atmosphere interactions and energy fluxes between the atmosphere and the ground

For a given MODIS pixel, the split-window LST algorithm requires emissivities in band 31 and 32. These values are estimated by determining the MODIS/IGBP class and looking up the emissivity value in a table.

After geometric correction of the image, LST of clear-sky pixels in MODIS scenes is retrieved from brightness temperatures in bands 31 and 32 in generalized split-window algorithm. The coefficient used in the split window algorithm are given by a LUT(Look-up table).

LST is defined by the radiation emitted by the Land surface observed by MODIS at instant viewing angles. Also sensor zenith angles used in split window algorithm for increase of accuracy. The split-window method corrects for atmosphere effects based on the differential absorption in adjacent infrared bands.

Results compared using ASTER data acquired with same date and time. One study site selected: a semi-arid area located in south of Iran. The ASTER estimates were derived using the Temperature Emissivity Separation (TES) algorithm. The MODIS and ASTER temperature retrievals were in good agreement. It was shown that Classification-based emissivity is a good way for retrieval of temperature is Iran if Land-cover map would be refined with more information in the classification look-up scheme. In conclusion, the MODIS infrared images, because of their radiometric and spectral resolution and extensive swath width band can be useful for retrieval of LST map from Iran in different time periods for scientist study.

The transportation of road construction material costs a major amount of the project cost of a Road Construction. It is estimated that around 20% of total costs is in the form of cost of Transportation. Using the GIS to find the optimal path between construction site and Quarry can help in saving great amount of cost and time. GIS software available nowadays has built-up functions to find the closest facility and shortest path. An attempt has been made to obtain the optimal cost route in the state of Uttar Pradesh between the important towns and Quarries. The Topographic maps were obtained from Survey of India (SOI) and the details of quarries were obtained from the reports of Pradhan Mantri Gram Sadak Yojana (PMGSY). ArcGIS 9.0 and ArcVIew Network Analyst 3.0 were the GIS software used and Avenue Scripts for Graphical User Interface development.

In the present work optimal route for the closest quarry of road construction material was found out using GIS. The work involved scanning the paper maps, Georeferencing them and Digitising the features to suitable shapefiles in ArcGIS. Roads were divided into National Highway (NH), State Highway (SH) and Major District Road (MDR). and digitized in polyline shapefiles. Towns and Quarries were digitized in Point shapefiles. The closest quarry from a given town was obtained and shortest path and cost route were found out using ArcView Network Analyst. The cost route can be based on time of travel and velocity. A Graphical User Interface was developed in which one can give the location of site of construction and required material. It will automatically calculate the closest quarry and the path in terms of length. There are options for getting cost route based on time and velocity also. Also different Data used and shapefiles developed in the project can be viewed. The whole GUI is developed in ArcView using Avenue scripts.

This work will be useful for contractors and construction engineers to obtain suitable material through the nearest or the cost effective route and hence reducing the cost of construction by effectively reducing cost of transportation of road construction material. The user interface developed will assist those who don’t know the GIS software to obtain the results.