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The 23 papers in this special issue are grouped into the following headings: 1) Instrumentation, Calibration, Validation, and Processing; 2) Ocean Applications; 3) Land Applications (soil moisture, vegetation, and land freeze/thaw cycles); 4) Polar Snow and Ice Applications. [ABSTRACT FROM AUTHOR]

A preface to the 2012 issue of "Marine Geodesy" is presented.

An introduction is presented in which the editor discusses various reports within the issue on topics including calibration through radar transponders, climate data record creation and sea surface and geoid models.

The effects of large-scale human intervention on inlet dynamics are studied. In particular, the response of the largest of the Wadden Sea inlets (Texel Inlet) to the closure of a major part of its inner basin is re-analyzed. The re-analysis is based on datasets of bathymetry, discharges and water levels that have been obtained by intensive monitoring of both the inner basin and the ebb-tidal delta. Based on this re-analyisis and modern theoretical knowledge a conceptual model is postulated that describes the morphologic adjustment of tidal inlets due to large-scale human intervention. The kernel of this model is that the morphological adjustment towards a new overall equilibrium is split into two stages related to the existence of more than one temporal response scale. [ABSTRACT FROM AUTHOR]

The Ocean Surface Topography Mission/Jason-2 (OSTM/Jason-2) satellite altimetry mission was successfully launched on June 20, 2008, as a cooperative mission between CNES, EUMETSAT, NASA, and NOAA. OSTM/Jason-2 will continue to precisely measure the surface topography of the oceans and continental surface waters, following on the same orbit as its predecessors, TOPEX/Poseidon and Jason-1. To maintain the high-accuracy measurements, the mission carries a dual-frequency altimeter, a three-frequency microwave radiometer, and three precise positioning systems. The objectives of the mission are both operational and scientific. The mission will provide near-real time high-precision altimetric measurements for integration into ocean forecasting models and other products. The mission will also extend the precise surface topography time series started by TOPEX/Poseidon in 1992 over two decades in order to study long-term ocean variations such as mean sea level variations and interannual and decadal oscillations. The measurement system has been adapted to provide quality data nearer to the coasts, and over lakes and rivers. This paper provides an overview of the OSTM/Jason-2 mission in terms of the system design and a brief introduction to the science objectives. [ABSTRACT FROM AUTHOR]

The Advanced Scatterometer (ASCAT) onboard the Metop-A satellite became operational shortly after launch in 2006, and an absolute calibration using three transponders was achieved in November 2008. In this paper, we describe how the CMOD5.n ocean backscatter geophysical model function (GMF), which was derived using data from previous scatterometers onboard the European Remote Sensing 1 and 2 satellites (ERS-1 and ERS-2), was used to derive backscatter bias correction factors. The purpose is to remove the bias between ASCAT backscatter data and the CMOD5.n GMF output which allows these data to be used in place of ERS data in existing wind processing algorithms. The ASCAT Wind Data Processor, developed at the Royal Netherlands Meteorological Institute (KNMI), applies the bias correction factors to ASCAT data and uses CMOD5.n to retrieve wind vectors in order to produce an operational wind product. This resulted in a stable and high-quality ASCAT wind product since February 2007. We validate this product by comparing it to the European Centre for Medium-range Weather Forecasts (ECMWF) winds and buoy measurements. The bias correction factors indicate that ASCAT data and the GMF differ by roughly 0.3 dB below 55° and up to 0.8 dB above 55°. A possible explanation lies in CMOD5.n which has been poorly validated in this incidence angle regime. Validation of ASCAT data using the ocean calibration method confirms this result and also indicates that bias-corrected data are everywhere within 0.3 dB of CMOD5.n. The wind product validation shows an rms error of 1.3 m ⋅ s-1 in wind speed and 16° in wind direction when compared to ECMWF winds. This is better than the results achieved using ERS scatterometer data. Against buoy winds, we find an rms error wind component error of approximately 1.8 m ⋅ s-1. These results show that the ASCAT wind product is of high quality and satisfies its wind component accuracy requirement of 2 m ⋅ s-1. [ABSTRACT FROM AUTHOR]

A two-dimensional variational ambiguity removal technique (2DVAR) is presented. It first makes an analysis based on the ambiguous scatterometer wind vector solutions and a model forecast, and next selects the ambiguity closest to the analysis as solution. 2DVAR is applied on SeaWinds scatterometer data and its merits for nowcasting applications are shown in a general statistical comparison with model forecasts and buoy observations, and in a number of case studies. The sensitivity of 2DVAR to changes in the parameters of its underlying error model is studied. It is shown that observational noise in the nadir swath of SeaWinds is effectively suppressed by application of 2DVAR in combination with the multisolution scheme (MSS). MSS retains the local wind vector probability density function after inversion, rather than only a limited number of ambiguous solutions. As a consequence, the influence of the background increases, but this can be mitigated by switching off variational quality control. A case study on an extratropical cyclone of hurricane force intensity observed with SeaWinds at 25-km resolution shows that reliable wind estimates can be obtained for wind speeds up to 40 m s-1 and more. At 25 km, the results of 2DVAR with MSS compare better with buoy measurements than with the ECMWF model. At 100-km resolution this is reversed, proving that 2DVAR retrieves small-scale features absent in the ECMWF model. [ABSTRACT FROM AUTHOR]

The article provides information about the EUMETSAT Polar System and the Metop satellites. It will be the first series of polar-orbiting satellites in Europe for its operational meteorology and climate monitoring wherein it will be providing services until the year 2020. It is the European contribution to the Initial Joint Polar System, a joint European-U.S. operational polar satellite system that serves in the midmorning orbit. The Metop satellites are comprised of Service Module (SVM) and Payload Module (PLM) with solar array. Key products of EPS and Metop include atmospheric sounding radiances, radar backscatter triplets, ozone profile information, and others.