11-10-2014, 04:27 PM
DEVELOPMENT OF A MATLAB BASED MODULE FOR CLIMATE DATA FORMAT CONVERSION
[attachment=69005]
ISRO
(INDIAN SPACE RESEARCH ORGANISATION)
The Indian Space Research Organisation (ISRO, BhāratīyaAntarikṣaAnusandhānaSaṅgaṭhana) is the primary space agency of India. ISRO is amongst the largest government space agencies in the world. Its primary objective is to advance space technology and use its applications for national benefit.
Established in 1969, ISRO superseded the erstwhile Indian National Committee for Space Research (INCOSPAR). Headquartered inBengaluru, ISRO is under the administrative control of the Department of Space, Government of India.
Since its establishment, ISRO has achieved numerous milestones. It built India's first satellite, Aryabhata, which was launched by theSoviet Union on 19 April in 1975.For launching satellites into polar orbits and the Geosynchronous Satellite LaunchVehicle (GSLV) for placing satellites into geostationary orbits. These rockets have launched numerous communications satellites and earth observation satellite. On 22 October in 2008, C1980, Rohini became the first satellite to be placed in orbit by an Indian-made launch vehicle,SLV-3. ISRO subsequently developed two other rockets: the Polar Satellite Launch Vehicle (PSLV)handrayaan-1, India sent its first mission to the Moon. Over the years, ISRO has conducted a variety of operations for both Indian and foreign clients. ISRO's satellite launch capability is mostly provided by indigenous launch vehicles and launch sites. In 2008, ISRO successfully launched its first lunar probe, Chandrayaan-1, while future plans include indigenous development of GSLV, manned space missions, further lunar exploration, mars exploration and interplanetary probes. ISRO has several field installations as assets, and cooperates with the international community as a part of several bilateral and multilateral agreements. 5 November 2013, ISRO launched its Mars Orbiter Mission, which is currently en route to Mars.
The June 2014 launch of five foreign satellites by the PSLV (Polar Satellite Launch Vehicle) became an impetus for PM NarendraModi to proclaim his ability of showcasing India as a champion of its neighboring countries, and thus envisioning a developement of a satellite which will be used by its neighbouring countries, as a gift from India.
GOALS AND OBJECTIVES:
The prime objective of ISRO is to develop space technology and its application to various national tasks. The Indian space programme was driven by the vision of Dr Vikram Sarabhai, considered the father of Indian Space Programme. As he said in 1969:
“ There are some who question the relevance of space activities in a developing nation. To us, there is no ambiguity of purpose. We do not have the fantasy of competing with the economically advanced nations in the exploration of the Moon or the planets or manned space-flight. But we are convinced that if we are to play a meaningful role nationally, and in the community of nations, we must be second to none in the application of advanced technologies to the real problems of man and society. ”
INTRODUCTION
CLIMATE DATA:
Climate is a measure of the average pattern of variation in temperature, humidity, atmospheric pressure,wind, precipitation, atmospheric particle count and other meteorological variables in a given region over long periods of time. Climate is different from weather, in that weather only describes the short-term conditions of these variables in a given region.
A region's climate is generated by the climate system, which has five components: atmosphere,hydrosphere, cryosphere, land surface, and biosphere.
The climate of a location is affected by its latitude, terrain, and altitude, as well as nearby water bodies and their currents. Climates can be classified according to the average and the typical ranges of different variables, most commonly temperature and precipitation. The most commonly used classification scheme was originally developed by WladimirKöppen. The Thornthwaite system, in use since 1948, incorporatesevapotranspiration along with temperature and precipitation information and is used in studying animal species diversity and potential effects of climate changes. The Bergeron and Spatial Synoptic Classification systems focus on the origin of air masses that define the climate of a region.
The climate data consists of the following attributes:
1) TEMPERATURE
2) RAINFALL
3) HUMIDITY
4) PRECIPITATION
) RAINFALL
The major cause of rain production is moisture moving along three-dimensional zones of temperature and moisture contrasts known as weather fronts. If enough moisture and upward motion is present, precipitation falls from convective clouds (those with strong upward vertical motion) such as cumulonimbus (thunder clouds) which can organize into narrow rainbands. In mountainous areas, heavy precipitation is possible where upslope flow is maximized within windward sides of the terrain at elevation which forces moist air to condense and fall out as rainfall along the sides of mountains. On the leeward side of mountains, desert climates can exist due to the dry air caused by downslope flow which causes heating and drying of the air mass. The movement of the monsoon trough, or intertropical convergence zone, brings rainy seasons to savannah climes.
HUMIDITY:
Humidity is the amount of water vapor in the air. Water vapor is the gaseous state of water and is invisible. Humidity indicates the likelihood of precipitation, dew, or fog. Higher humidity reduces the effectiveness of sweating in cooling the body by reducing the rate ofevaporation of moisture from the skin. This effect is calculated in a heat index table or humidex, used during summer weather.
There are three main measurements of humidity: absolute, relative and specific. Absolute humidity is the water content of air. Relative humidity, expressed as a percent, measures the current absolute humidity relative to the maximum for that temperature. Specific humidity is a ratio of the water vapor content of the mixture to the total air content on a mass basis.
PRECIPITATION:
In meteorology, precipitation is any product of the condensation of atmospheric water vapour that falls under gravity. The main forms of precipitation include drizzle, rain, sleet, snow, graupel and hail. Precipitation occurs when a local portion of the atmosphere becomes saturated with water vapour, so that the water condenses and "precipitates". Thus, fog and mist are not precipitation but suspensions because the water vapour does not condense sufficiently to precipitate. Two processes, possibly acting together, can lead to air becoming saturated: cooling the air or adding water vapour to the air. Generally, precipitation will fall to the surface; an exception is virga which evaporates before reaching the surface. Precipitation forms as smaller droplets coalesce via collision with other rain drops or ice crystals within acloud. Rain drops range in size from oblate, pancake-like shapes for larger drops, to small spheres for smaller drops. Unlike raindrops, snowflakes grow in a variety of different shapes and patterns, determined by the temperature and humidity characteristics of the air the snowflake moves through on its way to the ground. While snow and ice pellets require temperatures close to the ground to be near or below freezing, hail can occur during much warmer temperature regimes due to the process of its formation.
WHAT IS MATLAB?
MATLAB (matrix laboratory) is a multi-paradigm numerical computing environment and fourth-generation programminglanguage. Developed by MathWorks, MATLAB allows matrix manipulations, plotting of functions and data, implementation ofalgorithms, creation of user interfaces, and interfacing with programs written in other languages, including C, C++, Java, and Fortran.
Although MATLAB is intended primarily for numerical computing, an optional toolbox uses the MuPAD symbolic engine, allowing access to symbolic computing capabilities. An additional package, Simulink, adds graphical multi-domain simulation and Model-Based Design for dynamic and embedded systems.
In 2004, MATLAB had around one million users across industry and academia. MATLAB users come from various backgrounds of engineering, science, and economics. MATLAB is widely used in academic and research institutions as well as industrial enterprises.
Cleve Moler, the chairman of the computer science department at the University of New Mexico, started developing MATLAB in the late 1970s.He designed it to give his students access to LINPACK and EISPACK without them having to learn Fortran. It soon spread to other universities and found a strong audience within the appliedmathematics community. Jack Little, an engineer, was exposed to it during a visit Moler made to Stanford University in 1983. Recognizing its commercial potential, he joined with Moler and Steve Bangert. They rewrote MATLAB in C and founded MathWorks in 1984 to continue its development. These rewritten libraries were known as JACKPAC. In 2000, MATLAB was rewritten to use a newer set of libraries for matrix manipulation, LAPACK.
MATLAB was first adopted by researchers and practitioners in control engineering, Little's specialty, but quickly spread to many other domains. It is now also used in education, in particular the teaching of linear algebra and numerical analysis, and is popular amongst scientists involved in image processing
WHAT IS NETCDF?
NetCDF (Network Common Data Form) is a set of software libraries and self-describing, machine-independent data formats that support the creation, access, and sharing of array-oriented scientific data. The project homepage is hosted by the Unidata program at the University Corporation for Atmospheric Research (UCAR). They are also the chief source of netCDF software, standards development, updates, etc. The format is an open standard.NetCDF Classic and 64-bit Offset Format are an international standard of the Open Geospatial Consortium.
The project started in 1989 and is still actively supported by UCAR. Version 3.x (released in 1997) is still widely used across the world and maintained by UCAR (last update 2012). Version 4.0 (released in 2008) allows the use of the HDF5 data file format. Version 4.1 (2010) adds support for C and FORTRAN client access to specified subsets of remote data via OPeNDAP. Both Version 3 and Version 4 are planned to be updated by UCAR.
The format was originally based on the conceptual model of the Common Data Format developed by NASA, but has since diverged and is not compatible with it.
The netCDF libraries support 3 different binary formats for netCDF files:
• The classic format was used in the first netCDF release, and is still the default format for file creation.
• The 64-bit offset format was introduced in version 3.6.0, and it supports larger variable and file sizes.
• The netCDF-4/HDF5 format was introduced in version 4.0; it is the HDF5 data format, with some restrictions.
All formats are "self-describing". This means that there is a header which describes the layout of the rest of the file, in particular the data arrays, as well as arbitrary file metadata in the form of name/value attributes. The format is platformindependent, with issues such as endianness being addressed in the software libraries. The data are stored in a fashion that allows efficient subsetting.
Starting with version 4.0, the netCDF API allows the use of the HDF5 data format. NetCDF users can create HDF5 files with benefits not available with the netCDF format, such as much larger files and multiple unlimited dimensions.
Full backward compatibility in accessing old netCDF files and using previous versions of the C and Fortran APIs is supported.
A wide range of application software has been written which makes use of netCDF files. These range from command line utilities to graphical visualization packages. A number are listed below, and a longer list is on the UCAR website.
• A commonly used set of Unix command line utilities for netCDF files is the NetCDF Operators (NCO) suite, which provide a range of commands for manipulation and analysis of netCDF files including basic record concatenating, slicing and averaging.
• NcBrowse is a generic netCDF file viewer that includes Java graphics, animations and 3D visualizations for a wide range of netCDF file conventions.
• Ncview is a visual browser for netCDF format files. This program is a simple, fast, GUI-based tool for visualising fields in a netCDF file. One can browse through the various dimensions of a data array, taking a look at the raw data values. It is also possible to change color maps, invert the data, etc.
• Panoplyis a netCDF file viewer developed at the NASA Goddard Institute for Space Studies which focuses on presentation of geo-gridded data. It is written in Java and thus platform independent. Although its feature set overlaps with ncBrowse and ncview, Panoply is distinguished by offering a wide variety of map projections and ability to work with different scale color tables.
• The NCAR Command Language is used to analyze and visualize data in netCDF files (among other formats).
• PyNIO is a Python programming language module that allows read and/or write access to a variety of data formats, including netCDF.
• Ferret is an interactive computer visualization and analysis environment designed to meet the needs of oceanographers and meteorologists analyzing large and complex gridded data sets. Ferret offers a Mathematica-like approach to analysis; new variables may be defined interactively as mathematical expressions involving data set variables. Calculations may be applied over arbitrarily shaped regions. Fully documented graphics are produced with a single command.
• The Grid Analysis and Display System (GrADS) is an interactive desktop tool that is used for easy access, manipulation, and visualization of earth science data. GrADS has been implemented worldwide on a variety of commonly used operating systems and is freely distributed over the Internet.
• NCDF_Browser is a visual nCDF browser, written in the IDL programming language. Variables, attributes, and dimensions can be immediately downloaded to the IDL command line for further processing. All the Coyote Library files necessary to run nCDF_Browser are available in the zip file.
• ArcGIS versions after 9.2 support netCDF files that follow the Climate and Forecast Metadata Conventions and contain rectilinear grids with equally-spaced coordinates. The Multidimensional Tools toolbox can be used to create raster layers, feature layers, and table views from netCDF data in ArcMap, or convert feature, raster, and table data to netCDF.
• The Geospatial Data Abstraction Library provides support for read and write access to netCDF data.
Syntax
xlswrite(filename, M, sheet)
xlswrite(filename, M, sheet) writes matrix M to the specified worksheet sheet in the file filename. The sheet argument can be either a positive, double scalar value representing the worksheet index, or a quoted string containing the sheet name. The sheet argument cannot contain a colon.
If sheet does not exist, xlswrite adds a new sheet at the end of the worksheet collection. If sheet is an index larger than the number of worksheets, xlswrite appends empty sheets until the number of worksheets in the workbook equals sheet. In either case, xlswrite generates a warning indicating that it has added a new worksheet
[attachment=69005]
ISRO
(INDIAN SPACE RESEARCH ORGANISATION)
The Indian Space Research Organisation (ISRO, BhāratīyaAntarikṣaAnusandhānaSaṅgaṭhana) is the primary space agency of India. ISRO is amongst the largest government space agencies in the world. Its primary objective is to advance space technology and use its applications for national benefit.
Established in 1969, ISRO superseded the erstwhile Indian National Committee for Space Research (INCOSPAR). Headquartered inBengaluru, ISRO is under the administrative control of the Department of Space, Government of India.
Since its establishment, ISRO has achieved numerous milestones. It built India's first satellite, Aryabhata, which was launched by theSoviet Union on 19 April in 1975.For launching satellites into polar orbits and the Geosynchronous Satellite LaunchVehicle (GSLV) for placing satellites into geostationary orbits. These rockets have launched numerous communications satellites and earth observation satellite. On 22 October in 2008, C1980, Rohini became the first satellite to be placed in orbit by an Indian-made launch vehicle,SLV-3. ISRO subsequently developed two other rockets: the Polar Satellite Launch Vehicle (PSLV)handrayaan-1, India sent its first mission to the Moon. Over the years, ISRO has conducted a variety of operations for both Indian and foreign clients. ISRO's satellite launch capability is mostly provided by indigenous launch vehicles and launch sites. In 2008, ISRO successfully launched its first lunar probe, Chandrayaan-1, while future plans include indigenous development of GSLV, manned space missions, further lunar exploration, mars exploration and interplanetary probes. ISRO has several field installations as assets, and cooperates with the international community as a part of several bilateral and multilateral agreements. 5 November 2013, ISRO launched its Mars Orbiter Mission, which is currently en route to Mars.
The June 2014 launch of five foreign satellites by the PSLV (Polar Satellite Launch Vehicle) became an impetus for PM NarendraModi to proclaim his ability of showcasing India as a champion of its neighboring countries, and thus envisioning a developement of a satellite which will be used by its neighbouring countries, as a gift from India.
GOALS AND OBJECTIVES:
The prime objective of ISRO is to develop space technology and its application to various national tasks. The Indian space programme was driven by the vision of Dr Vikram Sarabhai, considered the father of Indian Space Programme. As he said in 1969:
“ There are some who question the relevance of space activities in a developing nation. To us, there is no ambiguity of purpose. We do not have the fantasy of competing with the economically advanced nations in the exploration of the Moon or the planets or manned space-flight. But we are convinced that if we are to play a meaningful role nationally, and in the community of nations, we must be second to none in the application of advanced technologies to the real problems of man and society. ”
INTRODUCTION
CLIMATE DATA:
Climate is a measure of the average pattern of variation in temperature, humidity, atmospheric pressure,wind, precipitation, atmospheric particle count and other meteorological variables in a given region over long periods of time. Climate is different from weather, in that weather only describes the short-term conditions of these variables in a given region.
A region's climate is generated by the climate system, which has five components: atmosphere,hydrosphere, cryosphere, land surface, and biosphere.
The climate of a location is affected by its latitude, terrain, and altitude, as well as nearby water bodies and their currents. Climates can be classified according to the average and the typical ranges of different variables, most commonly temperature and precipitation. The most commonly used classification scheme was originally developed by WladimirKöppen. The Thornthwaite system, in use since 1948, incorporatesevapotranspiration along with temperature and precipitation information and is used in studying animal species diversity and potential effects of climate changes. The Bergeron and Spatial Synoptic Classification systems focus on the origin of air masses that define the climate of a region.
The climate data consists of the following attributes:
1) TEMPERATURE
2) RAINFALL
3) HUMIDITY
4) PRECIPITATION
) RAINFALL
The major cause of rain production is moisture moving along three-dimensional zones of temperature and moisture contrasts known as weather fronts. If enough moisture and upward motion is present, precipitation falls from convective clouds (those with strong upward vertical motion) such as cumulonimbus (thunder clouds) which can organize into narrow rainbands. In mountainous areas, heavy precipitation is possible where upslope flow is maximized within windward sides of the terrain at elevation which forces moist air to condense and fall out as rainfall along the sides of mountains. On the leeward side of mountains, desert climates can exist due to the dry air caused by downslope flow which causes heating and drying of the air mass. The movement of the monsoon trough, or intertropical convergence zone, brings rainy seasons to savannah climes.
HUMIDITY:
Humidity is the amount of water vapor in the air. Water vapor is the gaseous state of water and is invisible. Humidity indicates the likelihood of precipitation, dew, or fog. Higher humidity reduces the effectiveness of sweating in cooling the body by reducing the rate ofevaporation of moisture from the skin. This effect is calculated in a heat index table or humidex, used during summer weather.
There are three main measurements of humidity: absolute, relative and specific. Absolute humidity is the water content of air. Relative humidity, expressed as a percent, measures the current absolute humidity relative to the maximum for that temperature. Specific humidity is a ratio of the water vapor content of the mixture to the total air content on a mass basis.
PRECIPITATION:
In meteorology, precipitation is any product of the condensation of atmospheric water vapour that falls under gravity. The main forms of precipitation include drizzle, rain, sleet, snow, graupel and hail. Precipitation occurs when a local portion of the atmosphere becomes saturated with water vapour, so that the water condenses and "precipitates". Thus, fog and mist are not precipitation but suspensions because the water vapour does not condense sufficiently to precipitate. Two processes, possibly acting together, can lead to air becoming saturated: cooling the air or adding water vapour to the air. Generally, precipitation will fall to the surface; an exception is virga which evaporates before reaching the surface. Precipitation forms as smaller droplets coalesce via collision with other rain drops or ice crystals within acloud. Rain drops range in size from oblate, pancake-like shapes for larger drops, to small spheres for smaller drops. Unlike raindrops, snowflakes grow in a variety of different shapes and patterns, determined by the temperature and humidity characteristics of the air the snowflake moves through on its way to the ground. While snow and ice pellets require temperatures close to the ground to be near or below freezing, hail can occur during much warmer temperature regimes due to the process of its formation.
WHAT IS MATLAB?
MATLAB (matrix laboratory) is a multi-paradigm numerical computing environment and fourth-generation programminglanguage. Developed by MathWorks, MATLAB allows matrix manipulations, plotting of functions and data, implementation ofalgorithms, creation of user interfaces, and interfacing with programs written in other languages, including C, C++, Java, and Fortran.
Although MATLAB is intended primarily for numerical computing, an optional toolbox uses the MuPAD symbolic engine, allowing access to symbolic computing capabilities. An additional package, Simulink, adds graphical multi-domain simulation and Model-Based Design for dynamic and embedded systems.
In 2004, MATLAB had around one million users across industry and academia. MATLAB users come from various backgrounds of engineering, science, and economics. MATLAB is widely used in academic and research institutions as well as industrial enterprises.
Cleve Moler, the chairman of the computer science department at the University of New Mexico, started developing MATLAB in the late 1970s.He designed it to give his students access to LINPACK and EISPACK without them having to learn Fortran. It soon spread to other universities and found a strong audience within the appliedmathematics community. Jack Little, an engineer, was exposed to it during a visit Moler made to Stanford University in 1983. Recognizing its commercial potential, he joined with Moler and Steve Bangert. They rewrote MATLAB in C and founded MathWorks in 1984 to continue its development. These rewritten libraries were known as JACKPAC. In 2000, MATLAB was rewritten to use a newer set of libraries for matrix manipulation, LAPACK.
MATLAB was first adopted by researchers and practitioners in control engineering, Little's specialty, but quickly spread to many other domains. It is now also used in education, in particular the teaching of linear algebra and numerical analysis, and is popular amongst scientists involved in image processing
WHAT IS NETCDF?
NetCDF (Network Common Data Form) is a set of software libraries and self-describing, machine-independent data formats that support the creation, access, and sharing of array-oriented scientific data. The project homepage is hosted by the Unidata program at the University Corporation for Atmospheric Research (UCAR). They are also the chief source of netCDF software, standards development, updates, etc. The format is an open standard.NetCDF Classic and 64-bit Offset Format are an international standard of the Open Geospatial Consortium.
The project started in 1989 and is still actively supported by UCAR. Version 3.x (released in 1997) is still widely used across the world and maintained by UCAR (last update 2012). Version 4.0 (released in 2008) allows the use of the HDF5 data file format. Version 4.1 (2010) adds support for C and FORTRAN client access to specified subsets of remote data via OPeNDAP. Both Version 3 and Version 4 are planned to be updated by UCAR.
The format was originally based on the conceptual model of the Common Data Format developed by NASA, but has since diverged and is not compatible with it.
The netCDF libraries support 3 different binary formats for netCDF files:
• The classic format was used in the first netCDF release, and is still the default format for file creation.
• The 64-bit offset format was introduced in version 3.6.0, and it supports larger variable and file sizes.
• The netCDF-4/HDF5 format was introduced in version 4.0; it is the HDF5 data format, with some restrictions.
All formats are "self-describing". This means that there is a header which describes the layout of the rest of the file, in particular the data arrays, as well as arbitrary file metadata in the form of name/value attributes. The format is platformindependent, with issues such as endianness being addressed in the software libraries. The data are stored in a fashion that allows efficient subsetting.
Starting with version 4.0, the netCDF API allows the use of the HDF5 data format. NetCDF users can create HDF5 files with benefits not available with the netCDF format, such as much larger files and multiple unlimited dimensions.
Full backward compatibility in accessing old netCDF files and using previous versions of the C and Fortran APIs is supported.
A wide range of application software has been written which makes use of netCDF files. These range from command line utilities to graphical visualization packages. A number are listed below, and a longer list is on the UCAR website.
• A commonly used set of Unix command line utilities for netCDF files is the NetCDF Operators (NCO) suite, which provide a range of commands for manipulation and analysis of netCDF files including basic record concatenating, slicing and averaging.
• NcBrowse is a generic netCDF file viewer that includes Java graphics, animations and 3D visualizations for a wide range of netCDF file conventions.
• Ncview is a visual browser for netCDF format files. This program is a simple, fast, GUI-based tool for visualising fields in a netCDF file. One can browse through the various dimensions of a data array, taking a look at the raw data values. It is also possible to change color maps, invert the data, etc.
• Panoplyis a netCDF file viewer developed at the NASA Goddard Institute for Space Studies which focuses on presentation of geo-gridded data. It is written in Java and thus platform independent. Although its feature set overlaps with ncBrowse and ncview, Panoply is distinguished by offering a wide variety of map projections and ability to work with different scale color tables.
• The NCAR Command Language is used to analyze and visualize data in netCDF files (among other formats).
• PyNIO is a Python programming language module that allows read and/or write access to a variety of data formats, including netCDF.
• Ferret is an interactive computer visualization and analysis environment designed to meet the needs of oceanographers and meteorologists analyzing large and complex gridded data sets. Ferret offers a Mathematica-like approach to analysis; new variables may be defined interactively as mathematical expressions involving data set variables. Calculations may be applied over arbitrarily shaped regions. Fully documented graphics are produced with a single command.
• The Grid Analysis and Display System (GrADS) is an interactive desktop tool that is used for easy access, manipulation, and visualization of earth science data. GrADS has been implemented worldwide on a variety of commonly used operating systems and is freely distributed over the Internet.
• NCDF_Browser is a visual nCDF browser, written in the IDL programming language. Variables, attributes, and dimensions can be immediately downloaded to the IDL command line for further processing. All the Coyote Library files necessary to run nCDF_Browser are available in the zip file.
• ArcGIS versions after 9.2 support netCDF files that follow the Climate and Forecast Metadata Conventions and contain rectilinear grids with equally-spaced coordinates. The Multidimensional Tools toolbox can be used to create raster layers, feature layers, and table views from netCDF data in ArcMap, or convert feature, raster, and table data to netCDF.
• The Geospatial Data Abstraction Library provides support for read and write access to netCDF data.
Syntax
xlswrite(filename, M, sheet)
xlswrite(filename, M, sheet) writes matrix M to the specified worksheet sheet in the file filename. The sheet argument can be either a positive, double scalar value representing the worksheet index, or a quoted string containing the sheet name. The sheet argument cannot contain a colon.
If sheet does not exist, xlswrite adds a new sheet at the end of the worksheet collection. If sheet is an index larger than the number of worksheets, xlswrite appends empty sheets until the number of worksheets in the workbook equals sheet. In either case, xlswrite generates a warning indicating that it has added a new worksheet