Investigation of Cyprus thermal tenancy using nine year MODIS LST data and Fourier analysis
Land Surface Temperature (LST) is an extremely important parameter that controls the exchange of long wave radiation between surface and atmosphere. It is a good indicator of the energy balance at the Earth’s surface and it is one of the key parameters in the physics of land-surface processes on regional as well as global scale. This paper utilizes monthly night and day averaged LST MODIS imagery over Cyprus for a 9 year period.
Fourier analysis and Least squares estimation fitting are implemented to analyze mean daily data over Cyprus in an attempt to investigate possible temperature tenancy over these years and possible differences among areas with different land cover and land use, such as Troodos Mountain and Nicosia, the main city in the center of the island. The analysis of data over a long time period, allows questions such as whether there is a tenancy to temperature increase, to be answered in a statistically better way, provided that ‘noise’ is removed correctly. Dealing with a lot of data, always provides a more accurate estimation, but on the other hand, more noise in implemented on the data, especially when dealing with temperature which is subject to daily and annual cycles.
A brief description over semi-automated data acquisition and standardization using object-oriented programming and GIS-based techniques, will be presented. The paper fully describes the time series analysis implemented, the Fourier method and how it was used to analyze and filter mean daily data with high frequency. Comparison of mean monthly daily LST against day and night LSTs is also performed over the 9 year period in order to investigate whether use of the extended data series provide significant advantage over short.
This initial investigation about the increase rate of temperature over Cyprus indicates that there is a clear increase over the period 2003-2011. Adopting the factors from the LSE method, this total increase may vary from 0.5oC to 2.6oC across different land cover types. As the rate of thermal increase is a very important subject, and results from this study only agree in rise of temperature over Cyprus, further investigation is needed prior to any future predictions and projections. Additional data for the year 2012 have already been gathered in order to extend data over a decay span. Aqua and Terra data over the five year period 2003-2007 can be used to create prediction models which can then be verified using Aqua data for the next five years 2008-2012. At the same time, Fourier analysis and LSE need further investigation as the results are contra indicting. Further analysis with diurnal temperature values might lead to useful concussions about different land types and temperature trends over them.
Correlation of temperature increase rate with altitude and land cover should be performed in order to provide solid evidence that urban heat islands tend to have a strong increase of temperature. Further statistical analysis is necessary in order to verify results.
[Update 11.09.2013] Nevertheless, it is claimed that there is no fear of temperature rise and that we now entering the contemporary 'ice age' where the temperature will start to fall (http://www.dailymail.co.uk/news/article-2415191/Global-cooling-Arctic-ice-caps-grows-60-global-warming-predictions.html)
Fourier analysis and Least squares estimation fitting are implemented to analyze mean daily data over Cyprus in an attempt to investigate possible temperature tenancy over these years and possible differences among areas with different land cover and land use, such as Troodos Mountain and Nicosia, the main city in the center of the island. The analysis of data over a long time period, allows questions such as whether there is a tenancy to temperature increase, to be answered in a statistically better way, provided that ‘noise’ is removed correctly. Dealing with a lot of data, always provides a more accurate estimation, but on the other hand, more noise in implemented on the data, especially when dealing with temperature which is subject to daily and annual cycles.
A brief description over semi-automated data acquisition and standardization using object-oriented programming and GIS-based techniques, will be presented. The paper fully describes the time series analysis implemented, the Fourier method and how it was used to analyze and filter mean daily data with high frequency. Comparison of mean monthly daily LST against day and night LSTs is also performed over the 9 year period in order to investigate whether use of the extended data series provide significant advantage over short.
This initial investigation about the increase rate of temperature over Cyprus indicates that there is a clear increase over the period 2003-2011. Adopting the factors from the LSE method, this total increase may vary from 0.5oC to 2.6oC across different land cover types. As the rate of thermal increase is a very important subject, and results from this study only agree in rise of temperature over Cyprus, further investigation is needed prior to any future predictions and projections. Additional data for the year 2012 have already been gathered in order to extend data over a decay span. Aqua and Terra data over the five year period 2003-2007 can be used to create prediction models which can then be verified using Aqua data for the next five years 2008-2012. At the same time, Fourier analysis and LSE need further investigation as the results are contra indicting. Further analysis with diurnal temperature values might lead to useful concussions about different land types and temperature trends over them.
Correlation of temperature increase rate with altitude and land cover should be performed in order to provide solid evidence that urban heat islands tend to have a strong increase of temperature. Further statistical analysis is necessary in order to verify results.
[Update 11.09.2013] Nevertheless, it is claimed that there is no fear of temperature rise and that we now entering the contemporary 'ice age' where the temperature will start to fall (http://www.dailymail.co.uk/news/article-2415191/Global-cooling-Arctic-ice-caps-grows-60-global-warming-predictions.html)
