Land-atmosphere interaction patterns in southeastern South America using satellite products and climate models

Spennemann, Pablo C.; Salvia, M.; Ruscica, Romina; Sörensson, Anna A.; Grings, F.; Karszenbaum, H.

doi:10.1016/j.jag.2017.08.016

Cited by 29 publications

(37 citation statements)

References 40 publications

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“…In particular, the high SM variability observed in the so-called Southeastern South America (SESA) region can be explained by the intense summer precipitation over this region [52]. This pattern has also been observed with satellite SM products derived from higher microwave frequencies and climate models [53], and responds to strong land-atmosphere interactions in the region. The variability observed in northern latitudes is probably due to imperfect detection of ice/snow and poor temporal coverage (see Figure 4).…”

Section: Temporal Mean and Variance Of Smos Soil Moisture Retrievals mentioning

confidence: 67%

Dominant Features of Global Surface Soil Moisture Variability Observed by the SMOS Satellite

2019

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Soil moisture observations are expected to play an important role in monitoring global climate trends. However, measuring soil moisture is challenging because of its high spatial and temporal variability. Point-scale in-situ measurements are scarce and, excluding model-based estimates, remote sensing remains the only practical way to observe soil moisture at a global scale. The ESA-led Soil Moisture and Ocean Salinity (SMOS) mission, launched in 2009, measures the Earth's surface natural emissivity at L-band and provides highly accurate soil moisture information with a 3-day revisiting time. Using the first six full annual cycles of SMOS measurements (June 2010-June 2016), this study investigates the temporal variability of global surface soil moisture. The soil moisture time series are decomposed into a linear trend, interannual, seasonal, and high-frequency residual (i.e., subseasonal) components. The relative distribution of soil moisture variance among its temporal components is first illustrated at selected target sites representative of terrestrial biomes with distinct vegetation type and seasonality. A comparison with GLDAS-Noah and ERA5 modeled soil moisture at these sites shows general agreement in terms of temporal phase except in areas with limited temporal coverage in winter season due to snow. A comparison with ground-based estimates at one of the sites shows good agreement of both temporal phase and absolute magnitude. A global assessment of the dominant features and spatial distribution of soil moisture variability is then provided. Results show that, despite still being a relatively short data set, SMOS data provides coherent and reliable variability patterns at both seasonal and interannual scales. Subseasonal components are characterized as white noise. The observed linear trends, based upon one strong El Niño event in 2016, are consistent with the known El Niño Southern Oscillation (ENSO) teleconnections. This work provides new insight into recent changes in surface soil moisture and can help further our understanding of the terrestrial branch of the water cycle and of global patterns of climate anomalies. Also, it is an important support to multi-decadal soil moisture observational data records, hydrological studies and land data assimilation projects using remotely sensed observations.

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Section: Temporal Mean and Variance Of Smos Soil Moisture Retrievals mentioning

confidence: 67%

Dominant Features of Global Surface Soil Moisture Variability Observed by the SMOS Satellite

2019

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“…(). The two models have been used extensively over South America in different international projects such as CLARIS, CLARIS‐LPB and CORDEX (Menéndez et al ., , , ; Carril et al ., ; Ruscica et al ., , , ; Sánchez et al ., ; Falco et al ., ; Spennemann et al ., ; Zaninelli et al ., ). The spatial domain includes the South American continent and adjacent oceans at approximately 50 km resolution and the models were driven every 6 hr with boundary conditions from ERA‐Interim reanalysis (Dee et al ., ).…”

Section: Methodsmentioning

confidence: 99%

The diurnal cycle of precipitation over South America represented by five gridded datasets

Giles

Ruscica

Menéndez

2019

Intl Journal of Climatology

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A characterization of the diurnal cycle of precipitation (DCP) over the whole South America is still lacking in the literature and the scarcity of sub‐daily rain ground measurements limits the data available for analysis and forbids a correct validation of alternative datasets. In this paper we analyse the climatological mean DCP during the monsoon active season using five gridded datasets: two satellite precipitation estimates, two regional climate models and one reanalysis. Amazonia, the Brazilian Highlands, the northeastern South American coast, the Andes and the western Colombian coast are identified as the areas with most prominent DCPs. The afternoon convection triggered by solar heating over land and the coastal and topographic effects are the main modes of sub‐daily variability, based on an EOF decomposition of the 3 hourly mean precipitation fields. We explore the contribution of mean frequency and intensity to amount of precipitation and nighttime–daytime differences. In general, both models precipitate earlier and more frequently than the satellite products and do not reproduce correctly areas of observed predominant nighttime precipitation where mesoscale convective systems are active, like La Plata Basin or Amazonia. Over the analysed areas, the high frequency of precipitation is the driving mechanism of total amount in the models, whereas in the satellite products there is also considerable contribution from intensity. Overall, the reanalysis shows features in between the models and the satellite estimates, sharing characteristics with both types of data. The results presented here point at the diversity of sub‐daily precipitation characteristics in South America, the issues with conventional climate models and the uncertainty in satellite products and reanalyses. The growing interest in the DCP by the scientific community and the development of new techniques like convection permitting modelling will hopefully continue to improve our knowledge of the precipitation dynamics and its influence on climate.

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“…ERA5 has a finer spatial and temporal resolution and a better global balance of precipitation and evaporation than ERA‐Interim, among other improvements (Copernicus Climate Change Service (C3S), 2017). The version of RCA4 considered in this study is currently used within CORDEX (http://www.cordex.org) and has been used over South America in previous studies (Spennemann et al ., 2018; Falco et al ., 2019; Giles et al ., 2019; Menéndez et al ., 2019; Zaninelli et al ., 2019), to which the reader can refer for more information about the model's configuration and performance. The spatial resolution is 25 and 50 km for ERA5 and RCA4, respectively.…”

Section: Methodsmentioning

confidence: 99%

“…In particular, the SALLJ exit region is located within the La Plata Basin, where continental moisture recycling highly contributes to local precipitation (van der Ent et al ., 2010; Martinez and Dominguez, 2014; Zemp et al ., 2014) and is also known as a hotspot of land–atmosphere coupling, where surface fluxes depend on soil moisture conditions. Some land–atmosphere interaction studies have been carried out at the inter‐annual and intra‐seasonal time scale in this region (Ruscica et al ., 2014; 2015; 2016; Spennemann et al ., 2018; Menéndez et al ., 2019); however, many land–atmosphere processes are still poorly understood, mainly at the diurnal scale and especially how they influence precipitation. In general, global and regional studies have found that the coupling seems to favour afternoon precipitation preferably over strong soil moisture gradients (Taylor et al ., 2011; Petrova et al ., 2018), but its magnitude and the signal of the feedbacks can change depending on the background wind (Froidevaux et al ., 2014; Ford et al ., 2015; Holgate et al ., 2019) and the moisture flux convergence (Petrova et al ., 2018; Welty and Zeng, 2018).…”

Section: Introductionmentioning

confidence: 99%

Warm‐season precipitation drivers in northeastern Argentina: Diurnal cycle of the atmospheric moisture balance and land–atmosphere coupling

Giles

Ruscica

Menéndez

2020

Intl Journal of Climatology

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Southeastern South America is influenced by moisture transport from lower latitudes, sustains intense convective storms and is a land-atmosphere coupling hotspot, but the interconnection between these processes is still not well understood. We present the warm-season diurnal cycle climatology of the atmospheric water balance components in the South American Low-Level Jet (SALLJ) exit region in northeastern Argentina during 1998-2012. Different precipitation-based types of events (clear-sky and rainy days) were explored together with processes tied to the land-atmosphere coupling at the daily scale. Our research was based on simulations with and without soil moisture-atmosphere coupling with the RCA4 regional climate model. A control simulation was compared with a sensitivity simulation where the soil moisture was prescribed with the daily climatological values from the control run. The ERA5 reanalysis and the satellite precipitation products TRMM-3B42 v7 and CMORPH v1.0 bias-corrected were used for comparative purposes. From the diurnal water balance analysis, we found that moisture flux convergence in the region is the main driver for nocturnal precipitation while local evapotranspiration feeds afternoon rain events. Rainy afternoons do not show differences between simulations, but rainy nights seem to be affected. Moreover, daily correlations between surface and boundary-layer variables showed that the local coupling is weaker during rainy days than during clear-sky days. Therefore, we suggest that changes in non-local drivers, such as the moisture flux through the SALLJ, are more relevant for rainy nights than the local coupling.

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Land-atmosphere interaction patterns in southeastern South America using satellite products and climate models

Cited by 29 publications

References 40 publications

Dominant Features of Global Surface Soil Moisture Variability Observed by the SMOS Satellite

Dominant Features of Global Surface Soil Moisture Variability Observed by the SMOS Satellite

The diurnal cycle of precipitation over South America represented by five gridded datasets

Warm‐season precipitation drivers in northeastern Argentina: Diurnal cycle of the atmospheric moisture balance and land–atmosphere coupling

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