Comparison of seasonal hydrologic variations in the La Plata basin from GRACE monthly solutions with in situ gauge water level data

Abstract

Seasonal hydrologic variations have been determined in the La Plata basin from GRACE monthly solutions for a time span of less than 6 years. The results have been compared to tide gauge water level data along several rivers of the La Plata basin. Annual and semi-annual curves have been fitted both to the GRACE water storage variation series and to the tide gauge water level series, correlations between the original series and the curves have been determined, relationship of the amplitudes and phases have been investigated. The aim of the comparison is to detect time delay between the seasonal cycle of precipitation (related to GRACE) and runoff (observed by tide gauges). The time delay may deliver information on water storage, such as groundwater aquifers, soil moisture or canopy interception. As for the results, by the comparison of the annual phases, 11-13 days of time delay between GRACE data and tide gauge data has been detected.

Multi-annual mass variations from GRACE monthly solutions_preliminary results

“…The absence of the annual mass variations despite of the seasonality of the rainfall patterns can be originated in complex hydrologic processes. In one of our previous study, we have found that the lack of seasonal water mass variations is typical in the most of the La Plata basin due to the presence of massive dams, waterfalls and the Guarani aquifer (Kiss and Földváry, 2017). The ENSO events have the opposite effect compared to Canada.…”

A GRACE-FO első másfél éve

“…A GRACE küldetése során hónapról hónapra új modell meghatározására volt lehetőség, ami alapján a tömegeloszlás időbeli változásának hónapos mintavételezésű vizsgálata végezhető. Bár a hónapos adatmennyiség a nehézségi erőteret csak durva, több száz km-es felbontásban szolgáltatja, ezek kiválóak nagyobb területek éves periódusú (Kiss-Földváry 2015, 2017b és hosszú, akár több évtizedes lefolyású (Földváry-Mészáros 2009, Földváry 2012, Földváry et al 2015, Kiss-Földváry 2017a) tömegátrendeződéssel járó folyamatainak elemzésére és követésére. A GRACE-FO célja a GRACE által megkezdett hónapos idősor folytatása volt, amely (egyéves megszakítással ugyan) lehetővé teszi a vizsgált geofizikai és geodinamikai folyamatok folytatólagos követését (Földváry 2019).…”

Water Density Variations of the Aral Sea from GRACE and GRACE-FO Monthly Solutions

“…These two missions provide a unique tool for determining the temporal variations of gravity; consequently, the mass redistribution processes that have generated the gravity changes [4]. GRACE and GRACE-FO have become essential sources of data when monitoring the variation in water fluxes over large basins (e.g., the Mediterranean Sea [5], the Arabian Peninsula [6][7][8], Niger [9], Michigan [10], the Amazonas [11][12][13], the La Plata basins [14,15], the Nubian and Nile basins [16][17][18][19][20][21]), and for the analysis of climate changes via ice mass balance [22][23][24], sea level rise [25,26], ground water storage [27][28][29][30][31], and extreme precipitation [32]. In the present study, a GRACE-and GRACE-FO-based gravity anomaly time series is determined and utilized to analyze the desiccation process of the Aral Sea.…”