Continuous MODIS land surface temperature dataset over the Eastern Mediterranean

A continuous dataset of Land Surface Temperature (LST) is vital for climatological and environmental studies. LST can be regarded as a combination of seasonal mean temperature (climatology) and daily anomaly, which is attributed mainly to the synoptic-scale atmospheric circulation (weather). To reproduce LST in cloudy pixels, time series (2002-2019) of cloud-free 1km MODIS Aqua LST images were generated and the pixel-based seasonality (climatology) was calculated using temporal Fourier analysis. To add the anomaly, we used the NCEP Climate Forecast System Version 2 (CFSv2) model, which provides air surface temperature under both cloudy and clear sky conditions. The combination of the two sources of data enables the estimation of LST in cloudy pixels.

Data structure

The dataset consists of geo-located continuous LST (Day, Night and Daily) which calculates LST values of cloudy pixels. The spatial domain of the data is the Eastern Mediterranean, at the resolution of the MYD11A1 product (~1 Km). Data are stored in GeoTIFF format as signed 16-bit integers using a scale factor of 0.02, with one file per day, each defined by 4 dimensions (Night LST Cont., Day LST Cont., Daily Average LST Cont., QA). The QA band stores information about the presence of cloud in the original pixel. If in both original files, Day LST and Night LST there was NoData due to clouds, then the QA value is 0. QA value of 1 indicates NoData at original Day LST, 2 indicates NoData at Night LST and 3 indicates valid data at both, day and night. File names follow this naming convention: LST_ <YYYY_MM_DD> .tif, where <YYYY > represents the year, <MM> represents the month and <DD> represents the day. Files of each year (2002-2019) are compressed in a ZIP file. The same data is also provided in NetCDF format, each file represents a whole year and is consist of 4 bands (Night LST Cont., Day LST Cont., Daily Average LST Cont., QA) for each day.

The file LSTcont_validation.tif contains the validation dataset in which the MAE, RMSE, and Pearson (r) of the validation with true LST are provided. Data are stored in GeoTIFF format as signed 32-bit floats, with the same spatial extent and resolution as the LSTcont dataset. These data are stored with one file containing three bands (MAE, RMSE, and Perarson_r). The same data with the same structure is also provided in NetCDF format.

How to use

The data can be read in various of program languages such as Python, IDL, Matlab etc.and can be visualize in a GIS program such as ArcGis or Qgis. A short animation demonstrates how to visualize the data using the Qgis open source program is available in the project Github code reposetory.

Web application

The LST_cont web application (https://shilosh.users.earthengine.app/view/continuous-lst) is an Earth Engine app. The interface includes a map and a date picker. The user can select a date (July 2002 – present) and visualize LST_cont for that day anywhere on the globe. The web app calculate LST_cont on the fly based on ready-made global climatological files. The LST_cont can be downloaded as a GeoTiff with 5 bands in that order: Mean daily LST_cont, Night original LST, Night LST_cont, Day original LST, Day LST_cont. 

Code availability

Datasets for other regions can be easily produced by the GEE platform with the code provided project Github code reposetory.