Calibration/Data Assimilation Approach for Integrating GRACE Data into the WaterGAP Global Hydrology Model (WGHM) Using an Ensemble Kalman Filter: First Results

We introduce a new ensemble-based Kalman filter approach to assimilate GRACE satellite gravity data into the WaterGAP Global Hydrology Model. The approach (1) enables the use of the spatial resolution provided by GRACE by including the satellite observations as a gridded data product, (2) accounts for the complex spatial GRACE error correlation pattern by rigorous error propagation from the monthly GRACE solutions, and (3) allows us to integrate model parameter calibration and data assimilation within a unified framework. We investigate the formal contribution of GRACE observations to the Kalman filter update by analysis of the Kalman gain matrix. We then present first model runs, calibrated via data assimilation, for two different experiments: the first one assimilates GRACE basin averages of total water storage and the second one introduces gridded GRACE data at \(5^\circ\) resolution into the assimilation. We finally validate the assimilated model by running it in free mode (i.e., without adding any further GRACE information) for a period of 3 years following the assimilation phase and comparing the results to the GRACE observations available for this period.     

Absolute gravity determination with JILAG-3 — improved data evaluation and instrumental technics

In addition to the on-line data evaluation during the measurements with the absolute gravity meter JILAG-3, a subsequently more intensive examination of the measured time/distance data pairs is performed. This allows an additional assessment of the gravity results, the station quality and the measurement conditions. Sinusoidal disturbances in the raw data deteriorate the determination of gravity. Incoming microseisms affect the mean result of the free-fall experiments randomly after a large number of measurements. Instrumental vibrations of the gravity meter during the measurement procedure may influence the gravity result systematically. A station comparison indicates that a 30 Hz frequency is triggered by JILAG-3 itself and influences the measurements depending on the stability of the foundation. Using a mathematical filter it is possible to separate the deteriorations from the gravity acceleration. Up to now an improvement in the absolute accuracy of gravity after filtering could not be proved, but an increase of the precision is indicated.     

Impact of Climate Change and Variability on Irrigation Requirements: A Global Perspective

Anthropogenic climate change does not only affect water resources but also water demand. Future water and food security will depend, among other factors, on the impact of climate change on water demand for irrigation. Using a recently developed global irrigation model, with a spatial resolution of 0.5° by 0.5°, we present the first global analysis of the impact of climate change and climate variability on irrigation water requirements. We compute how long-term average irrigation requirements might change under the climatic conditions of the 2020s and the 2070s, as provided by two climate models, and relate these changes to the variations in irrigation requirements caused by long-term and interannual climate variability in the 20th century. Two-thirds of the global area equipped for irrigation in 1995 will possibly suffer from increased water requirements, and on up to half of the total area (depending on the measure of variability), the negative impact of climate change is more significant than that of climate variability.     

A comprehensive photometric study of the Algol-type eclipsing binary: BG Pegasi

This study presents new photometric observations of classical Algol type binary BG Peg with a δ Scuti component. The light curve modeling was provided with the physical parameters of the component stars in the BG Peg system for the first time. After modeling light curves in B and V filters, the eclipse and proximity effects were removed from the light curve to analyze intrinsic variations caused by the hotter component of the system. Frequency analysis of the residuals light represents the multi-mode pulsation of the more massive component of the BG Peg system at periods of 0.039 and 0.047 days. Two frequencies could be associated with non-radial (l = 2) modes. The total amplitude of the pulsational variability in the V light curve was found to be about 0.045 mag. The long-term orbital period variation of the system was also investigated for the first time. The O–C analysis indicates periodic variation superimposed on a downward parabola. The secular period variation means that the orbital period of the system is decreasing at a rate of ?5.5 seconds per century, probably due to the magnetic activity of the cooler component. The tilted sinusoidal O–C variation may be caused by the gravitational effect of an unseen component around the system.     

Future extreme events in European climate: an exploration of regional climate model projections

This paper compares how well satellite versus weather station measurements of climate predict agricultural performance in Brazil, India, and the United States. Although weather stations give accurate measures of ground conditions, they entail sporadic observations that require interpolation where observations are missing. In contrast, satellites have trouble measuring some ground phenomenon such as precipitation but they provide complete spatial coverage of various parameters over a landscape. The satellite temperature measurements slightly outperform the interpolated ground station data but the precipitation ground measurements generally outperform the satellite surface wetness index. In India, the surface wetness index outperforms station precipitation but this may be reflecting irrigation, not climate. The results suggest that satellites provide promising measures of temperature but that ground station data may still be preferred for measuring precipitation in rural settings.     

Der südwestliche Randbereich der Espinhaço-Zone,Minas Gerais,Brasilien

Zusammenfassung Die vorliegende Arbeit umfaßt eine Kartierung in präkambrischen Metamorphiten und Metasedimenten am SE-Rand des São-Francisco-Beckens. Als älteste Einheit finden sich die Präminas-Gesteine, die von der miogeosynklinalen Quarzitfazies der MinasSerie überlagert werden. Die jüngere São-Francisco-Serie liegt diskordant über den älteren Einheiten. Sie gliedert sich in eine grobklastische Randfazies, das Macaúbas, und eine feinklastische, karbonatische Beckenfazies, das Bambuí. Die São-Francisco-Serie wurde noch in die ausklingende Minas-Orogenese einbezogen. Die Minas- und Macaúbas-Quarzite wurden tektonisch intensiv verschuppt und über das Bambuí überschoben. Im Bambuí entwickelte sich nur ein flacher Faltenbau. Aufgrund der tektonischen und sedimentologischen Beziehungen wird angenommen, daß die São-Francisco-Serie die Molasse des Minas-Orogens darstellt.

---

This paper is based on geological mapping in Precambrian metamorphic rocks at the SE border of the São Francisco Basin. The oldest unit are the Preminas rocks, which are overlain by the miogeosynclinal, quartzitic facies of the Minas Series. These units are unconformably overlain by the younger São Francisco Series. The later is subdivided in a marginal facies with coarse-grained clastics, the Macaúbas, and a fine clastic and calcareous basin facies, the Bambuí. The São Francisco Series was involved in the final phase of the Minas orogeny. The quartzites of the Minas and Macaúbas are intensively thrust-faulted now overlying the Bambuí. In the Bambuí only large amplitude folding developed. Based on the tectonical and the sedimentological relations it is assumed that the São Francisco Series is the molasse of the Minas geosyncline.

---

Resumo É apresentado um mapeamento geológico em metamorfitos e metasedimentos précambrianos na borda SE da Bacia do São Francisco. A unidade mais antiga é constituida por rochas da Série Préminas. Sobrepõem-se quartzitos da Série Minas em fácies miogeosmclinal. A Série São Francisco, como unidade mais recente, jaz em discordância sôbre as séries mais antigas. Divide-se em duas fácies: uma marginal, o Macaúbas, com sedimentos clásticos grosseiros, e outra com sedimentos clásticos finos e carbonates, o Bambuí. A Série São Francisco foi afetada pela fase final da orogenese Minas. Os quartzitos da Série Minas e do Grupo Macaúbas mostram intenso falhamento de empurrão e foram acavalados sôbre o Bambuí. No Bambuí formaram-se apenas dobras amplas. Conclui-se pelas relações tectônicas e sedimentológicas, que a Série São Francisco constitue a molassa da geossinclinal Minas.

---

- -. , - , . - . . . . , - .