Land surface temperature (LST) is one of the key parameters in the physics of land surface processes from local through global scales. The importance of LST is being increasingly recognized and there is a strong interest in developing methodologies to measure LST from space. However, retrieving LST is still a challenging task since the LST retrieval problem is ill-posed. This paper reviews the current status of selected remote sensing algorithms for estimating LST from thermal infrared (TIR) data. A brief theoretical background of the subject is presented along with a survey of the algorithms employed for obtaining LST from space-based TIR measurements. The discussion focuses on TIR data acquired from polar-orbiting satellites because of their widespread use, global applicability and higher spatial resolution compared to geostationary satellites. The theoretical framework and methodologies used to derive the LST from the data are reviewed followed by the methodologies for validating satellite-derived LST. Directions for future research to improve the accuracy of satellite-derived LST are then suggested

Land Surface Temperature (LST) is increasingly important for various studies assessing land surface conditions, e.g., studies of urban climate, evapotranspiration, and vegetation stress. The Landsat series of satellites have the potential to provide LST estimates at a high spatial resolution, which is particularly appropriate for local or small-scale studies. Numerous studies have proposed LST retrieval algorithms for the Landsat series, and some datasets are available online. However, those datasets generally require the users to be able to handle large volumes of data. Google Earth Engine (GEE) is an online platform created to allow remote sensing users to easily perform big data analyses without increasing the demand for local computing resources. However, high spatial resolution LST datasets are currently not available in GEE. Here we provide a code repository that allows computing LSTs from Landsat 4, 5, 7, and 8 within GEE. The code may be used freely by users for computing Landsat LST as part of any analysis within GEE.

The variability of results from different automated methods of detection and tracking of extratropical cyclones is assessed in order to identify uncertainties related to the choice of method. Fifteen international teams applied their own algorithms to the same dataset—the period 1989–2009 of interim European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERAInterim) data. This experiment is part of the community project Intercomparison of Mid Latitude Storm Diagnostics (IMILAST; see www.proclim.ch/imilast/index.html). The spread of results for cyclone frequency, intensity, life cycle, and track location is presented to illustrate the impact of using different methods. Globally, methods agree well for geographical distribution in large oceanic regions, interannual variability of cyclone numbers, geographical patterns of strong trends, and distribution shape for many life cycle characteristics. In contrast, the largest disparities exist for the total numbers of cyclones, the detection of weak cyclones, and distribution in some densely populated regions. Consistency between methods is better for strong cyclones than for shallow ones. Two case studies of relatively large, intense cyclones reveal that the identification of the most intense part of the life cycle of these events is robust between methods, but considerable differences exist during the development and the dissolution phases.

An objective cyclone detection and tracking analysis is performed over an 18-yr period, for the Mediterranean basin. The high-resolution (1.125° × 1.125° grid) European Centre for Medium-Range Weather Forecasts data used in this study proved to be particularly suitable for the detection and tracking techniques and to identify subsynoptic-scale Mediterranean lows, which have often been underestimated in previous studies. The major characteristics of Mediterranean cyclones are examined and compared with other Northern Hemisphere depressions. Both cyclogenesis and cyclolysis regions are identified in the domain of study. In addition, characteristics of Mediterranean depressions, such as cyclone duration and intensity, as well as their persistence throughout the year, are shown to be quite variable for different formation areas. Overall, the regions where cyclogenesis is mainly controlled by topography, like the Gulf of Genoa and south of the Atlas Mountains, seem to generally account for the most in... Abstract An objective cyclone detection and tracking analysis is performed over an 18-yr period, for the Mediterranean basin. The high-resolution (1.125° × 1.125° grid) European Centre for Medium-Range Weather Forecasts data used in this study proved to be particularly suitable for the detection and tracking techniques and to identify subsynoptic-scale Mediterranean lows, which have often been underestimated in previous studies. The major characteristics of Mediterranean cyclones are examined and compared with other Northern Hemisphere depressions. Both cyclogenesis and cyclolysis regions are identified in the domain of study. In addition, characteristics of Mediterranean depressions, such as cyclone duration and intensity, as well as their persistence throughout the year, are shown to be quite variable for different formation areas. Overall, the regions where cyclogenesis is mainly controlled by topography, like the Gulf of Genoa and south of the Atlas Mountains, seem to generally account for the most in...

A general climatology of the main mechanisms involved in Mediterranean cyclogenesis is presented. A diagnostic study of both composite means and case studies is performed to analyze processes occurring in different seasons, and in different cyclogenetic regions within the same season. It is shown that cyclones that developed over the three most active areas in winter—the Gulf of Genoa, the Aegean Sea, and the Black Sea—are essentially subsynoptic lows, triggered by the major North Atlantic synoptic systems being affected by local orography and/or low-level baroclinicity over the northern Mediterranean coast. It is also suggested that cyclones in two, or all three, of these regions often occur consecutively, linked to the same synoptic system. In spring and summer, thermally induced lows become progressively more important, despite the existence of other factors, such as the Atlas Mountains contributing to lee cyclogenesis in northern Africa, or the extension of the Asian monsoon into the eastern ... Abstract A general climatology of the main mechanisms involved in Mediterranean cyclogenesis is presented. A diagnostic study of both composite means and case studies is performed to analyze processes occurring in different seasons, and in different cyclogenetic regions within the same season. It is shown that cyclones that developed over the three most active areas in winter—the Gulf of Genoa, the Aegean Sea, and the Black Sea—are essentially subsynoptic lows, triggered by the major North Atlantic synoptic systems being affected by local orography and/or low-level baroclinicity over the northern Mediterranean coast. It is also suggested that cyclones in two, or all three, of these regions often occur consecutively, linked to the same synoptic system. In spring and summer, thermally induced lows become progressively more important, despite the existence of other factors, such as the Atlas Mountains contributing to lee cyclogenesis in northern Africa, or the extension of the Asian monsoon into the eastern ...

Information on land surface properties finds applications in a range of areas related to weather forecasting, environmental research, hazard management and climate monitoring. Remotely sensed observations yield the only means of supplying land surface information with adequate time sampling and a wide spatial coverage. The aim of the Satellite Application Facility for Land Surface Analysis (Land-SAF) is to take full advantage of remotely sensed data to support land, land–atmosphere and biosphere applications, with emphasis on the development and implementation of algorithms that allow operational use of data from European Organization for the Exploitation of Meteorological Satellites (EUMETSAT) sensors. This article provides an overview of the Land-SAF, with brief descriptions of algorithms and validation results. The set of parameters currently estimated and disseminated by the Land-SAF consists of three main groups: (i) the surface radiation budget, including albedo, land surface temperature, and downward short- and longwave fluxes; (ii) the surface water budget (snow cover and evapotranspiration); and (iii) vegetation and wild-fire parameters.