T. Pekker's research while affiliated with University of Texas at Austin and other places

Publications (8)

Article
Full-text available
Caspian Sea level (CSL) has undergone substantial fluctuations during the past several hundred years. The causes over the entire historical period are uncertain, but we investigate here large changes seen in the past several decades. We use climate model-predicted precipitation (P), evaporation (E), and observed river runoff (R) to reconstruct long...
Article
Detailed and high-fidelity numerical simulations of the gravity field recovery from GRACE data processing are an effective tool to assess the signal and noise in the GRACE (Level-2) gravity field data products. We report the results from such numerical simulations, which include the effect of sensor noise as well as errors due to rapid (relative to...
Article
High-resolution gravity field time-variability estimates - if available with a low latency - serve multiple purposes. For science, it allows the exploration of its potential for assimilation or constraining near-real time geophysical models - as has been proposed by other authors for hydrological applications. For GRACE operations, it provides a qu...
Article
Full-text available
A new generation of Earth gravity field models called GGM02 are derived using approximately 14 months of data spanning from April 2002 to December 2003 from the Gravity Recovery And Climate Experiment (GRACE). Relative to the preceding generation, GGM01, there have been improvements to the data products, the gravity estimation methods and the backg...
Article
We estimate the global mean sea level (GMSL) change using TOPEX/Poseidon satellite radar altimeter measurements and in-vestigate possible contributions from water mass redistribution within the global hydrological cycle using a few numerical models. We examine the global mean sea level change at seasonal, interannual, and long-term time scales. The...
Article
Ocean bottom pressure variation is one of the major driving forces of space geodetic observables, including the Earth rotation, geocenter motion, and gravitational change, and plays an important role in understanding and interpreting the GRACE observation. We examine the ocean bottom pressure variations using two independent approaches based on sat...
Article
In this paper, we present some extended results of hydrological impacts on seasonal sea level change using a few different hydrological models and an updated steric model, and compare with the results of Chen et al. [Geophys. Res. Lett., 25 (19) (1998) 3555] and Minster et al. [Global Planet. Change, 20 (1999) 157]. Even though different hydrologic...
Article
Wet troposphere corrections to altimeter measurements calculated from the TOPEX/Poseidon (T/P) Microwave Radiometer (TMR) and the ERS-1 and ERS-2 Microwave Radiometers (EMR1 and EMR2) are compared to each other and to European Center for Medium-Range Weather Forecasts (ECMWF) model data. The most recently published correction algorithm for the EMR1...

Citations

... The Caspian Sea is the largest lake on Earth with an area of about 371,000 km 2 . Over the past few hundred years, the Caspian Sea level (CSL) has experienced substantial fluctuations up to several meters [1][2][3]. The Caspian Sea is located within an endorheic basin between Europe and Asia, and the CSL change is mainly controlled by water mass exchange between the Caspian Sea and Caspian drainage basin (see Figure 1) via river discharge, precipitation, and evaporation. ...
... Finally, the radiometer drift can also be detected by comparison with the WTC derived from meteorological numerical models. The instrumental WTC is preferred to the modeled correction since it provides a better estimation of the wet troposphere path delay with respect to precision, sensitivity and spatial sampling (Stum, 1994;Urban et al., 2001). However, the modeled corrections remain one of the few independent references to assess the long-term stability of the radiometer corrections. ...
... Kurtenbach et al. (2009) employed short-arc method (Mayer-Gürr et al. 2007) under the principle of Kalman smoothing to conduct the daily snapshot solution, but the stochastic behaviour of the gravity field has to be considered as a priori information. Kang et al. (2008) used traditional dynamic method to generate the so-called 'quick-look' solution with a moving-window strategy (with a window step of one day and window width of 15 d), but those solutions are also stabilized using regularization. An incomplete list of GRACE solutions with various temporal resolutions from different research groups can be found at http://icgem.gfz-potsdam.de/ICGEM/TimeSeries.html. ...
... L'introduction de l'article présente les motivations du travail. Jusqu'à maintenant, de nombreuses études ont étudié le cycle saisonnier des échanges d'eau entre les continents et les océans grâce aux modèles de surface et les données de Topex-Poséidon (par exemple : Cazenave et al. (2000), Chen et al. (2002)). Notre papier se focalise sur l'étude de la modification du cycle saisonnier de ces échanges d'eau. ...
... For example, higher temperatures will increase the energy demand for cooling, reduce the precipitation rate and degrade the water resources (Roshan et al., 2010;Roshan et al., 2011). Regarding the effect of global warming on lakes depth and surface area fluctuation, lots of studies have been run on simulation and prediction of such changes all around the world (Chelton et al.,1982;Fang et al.,1998;Cabanes et al.,2001;Chen et al.,2002;David et al.,2002;Bouzinac et al.,2003;Michael et al.,2009;Mooij et al.,2009;Moernaut et al.,2010). As lakes respond directly to climate changes, quantifying their sensitivity to possible potentials will provide crucial information for the assessment of water resources quality and aquatic ecosystems in future (IPCC, 1996;Hauser et al., 1997;Magnuson et al., 1997;Mulholland et al., 1997;Rouse et al., 1997;Schindler, 1997;Fang et al., 1999, Komatsu et al., 2007. ...
... The missions Gravity Recovery and Climate Experiment (GRACE) (Tapley et al, 2004) and Gravity Recovery and Interior Laboratory (GRAIL) (Zuber et al, 2013) demonstrated the benefits of measuring orbital changes along the line connecting two satellites and, in particular, the relative velocity by means of the inter-satellite radio tracking data Doppler shift (Wolff et al, 1969). GRACE and GRAIL inter-satellite observations were ~2-3 orders of magnitude more accurate than deep space tracking data leading to extremely precise determination of the gravity fields of the Earth (Tapley et al, 2005) and the Moon (Zuber et al, 2013), respectively. An accurate high-resolution mapping of celestial bodies' gravitational anomalies will require extremely precise radio tracking data to reveal the properties of their internal structures. ...