A5056657756- Climate variability and models
- Tropical and Extratropical Cyclones Research
- Meteorological Phenomena and Simulations
- Oceanographic and Atmospheric Processes
- Geophysics and Gravity Measurements
- Geology and Paleoclimatology Research
- Ocean Waves and Remote Sensing
- Ionosphere and magnetosphere dynamics
- Geomagnetism and Paleomagnetism Studies
- Geological Modeling and Analysis
- Atmospheric Ozone and Climate
- Groundwater and Isotope Geochemistry
- Precipitation Measurement and Analysis
- Karst Systems and Hydrogeology
- Nonlinear Dynamics and Pattern Formation
- Atmospheric aerosols and clouds
- Geophysics and Sensor Technology
- Geological and Tectonic Studies in Latin America
- Advanced Computational Techniques and Applications
- Plant Water Relations and Carbon Dynamics
- Flood Risk Assessment and Management
- Geological and Geophysical Studies
- Solar and Space Plasma Dynamics
- Geological and Geophysical Studies Worldwide
- GNSS positioning and interference
University of Wisconsin–Madison
2021-2025
University of Michigan
2020-2024
Universidade de São Paulo
2018-2023
Weatherford College
2023
Instituto de Geofísica y Astronomía
2023
NSF National Center for Atmospheric Research
2023
Abstract A better understanding of the relative roles internal climate variability and external contributions, from both natural (solar, volcanic) anthropogenic greenhouse gas forcing, is important to project future hydrologic changes. Changes in evaporative demand play a central role this context, particularly tropical areas characterized by high precipitation seasonality, such as savannah semi-desertic biomes. Here we present set geochemical proxies speleothems well-ventilated cave located...
Abstract In the Amazon basin, intense precipitation recycling across forest significantly modifies isotopic composition of rainfall (δ 18 O, δD). tropical hydrologic cycle, such an effect can be identified through deuterium excess (dxs), yet it remains unclear what environmental factors control dxs, increasing uncertainty dxs‐based paleoclimate reconstructions. Here we present a 4‐year record rainfall, monitored in northwestern basin. We analyze variations as function air mass history, based...
Abstract Convectively coupled waves (CCWs) over the Western Hemisphere are classified based on their governing thermodynamics. It is found that only tropical depressions (TDs; TD waves) satisfy criteria necessary to be considered a moisture mode, as in Rossby-like wave an earlier study. In this wave, water vapor fluctuations play much greater role thermodynamics than temperature fluctuations. Only eastward-propagating inertio-gravity (EIG) does govern Temperature and comparable roles all...
Abstract Observations of column water vapor in the tropics show significant variations space and time, indicating that it is strongly influenced by passage weather systems. It hypothesized many influencing systems are moisture modes, whose thermodynamics governed moisture. On basis four objective criteria, results suggest all oceanic convectively coupled tropical depression (TD)-like waves equatorial Rossby modes. These modes occur where horizontal gradient steep not content high. Despite...
Abstract This study introduces four univariate regional indices to improve the representation of intraseasonal rainfall variability across South America throughout year, focusing on Brazil. These are constructed using two distinct approaches: linear Empirical Orthogonal Functions (EOF) method and unsupervised machine‐learning Self‐Organizing Maps (SOM) technique. Both methods applied Outgoing Longwave Radiation (OLR) precipitation‐filtered anomalies in 30–90‐day band over American domain....
The relationship between the Madden–Julian oscillation (MJO) and seasonal cycle of intraseasonal rainfall variability in Amazon Basin (AB) are analysed using band‐pass‐filtered gauge‐based gridded data for 1980–2009 period. Intraseasonal events (IE) have been defined selected based on extreme values first principal component (PC1) time series, which comes from empirical orthogonal function (EOF) analysis applied to filtered over AB. A total 132 IEs were identified with an average...
Abstract A westward‐propagating Rossby‐like wave signal is found to explain a large fraction of the intraseasonal variance in cloud brightness over Western Hemisphere. series diagnostic criteria suggest that this moisture mode: its anomalies dominate distribution moist static energy (MSE) and are phase with precipitation anomalies; thermodynamic equation obeys weak temperature gradient approximation. The propagates westward due zonal advection by mean flow maintained radiative heating...
Abstract Observations have shown that tropical convection is influenced by fluctuations in temperature and moisture the lower free troposphere (LFT; 600–850 hPa), as well moist enthalpy (ME) beneath 850 hPa level, referred to deep boundary layer (DBL; 850–1000 hPa). A framework developed consolidates these three quantities within context of buoyancy an entraining plume. “plume equation” derived based on a relaxed version weak gradient (WTG) approximation. Analysis this equation using from...
Abstract The moist processes of the Madden‐Julian Oscillation (MJO) in Coupled Model Intercomparison Project Phase 6 models are assessed using moisture mode theory‐based diagnostics over Indian Ocean (10°S–10°N, 75°E–100°E). Results show that no model can capture all properties relative to reanalysis. Most satisfy weak temperature gradient balance but have unrealistically fast MJO propagation and a lower moisture‐precipitation correlation. Models most criteria reliably simulate stronger MJO....
Abstract Rainfall over tropical South America is known to be modulated by convectively coupled Kelvin waves (CCKWs). In this work, the origin and dynamical features of American are revisited using satellite-observed brightness temperature, radiosonde, reanalysis datasets. Two main types CCKWs Amazon considered: with a Pacific precursor, precursor originating America. Amazonian CCKW’s associated preexisting convection in eastern account for about 35% total events. The cases precursors either...
Abstract The Radon and Hilbert transform their applications to convectively coupled waves (CCWs) are reviewed. Transform is used compute the wave envelope, whereas estimate phase group velocities of CCWs. Together, they provide an objective method understand CCW propagation. Results reveal speeds for fast (mixed Rossby‐gravity, westward eastward inertio‐gravity, Kelvin) that consistent with previous studies Matsuno's equatorial dispersion curves. However, slowly‐propagating tropical...
Instead of using the traditional space-time Fourier analysis filtered specific atmospheric fields, a normal-mode decomposition method was used to analyze South American intraseasonal variability (ISV). Intraseasonal examined separately in 30–90-day band, 20–30-day and 10–20-day band. The most characteristic structure time-scale, three bands, dipole-like convection between Atlantic Convergence Zone (SACZ) central-east America (CESA) region. In convective circulation patterns were modulated by...
ABSTRACT This study assesses the capabilities and limitations of state‐of‐the‐art European Centre for Medium‐Range Weather Forecasts (ECMWF) subseasonal to seasonal (S2S) model in forecasting precipitation a regional intraseasonal oscillation index over Brazil. Distinct from previous studies, we employ rather than global one, enabling more focused analysis complex variability. Weekly accumulated forecasts are evaluated against satellite‐derived data selected regions within Our findings...
The Madden Julian Oscillation (MJO) is the dominant element of atmospheric variability  in tropics on intraseasonal zonal timescales. MJO manifests itself as a slowly eastward propagating envelope coupling large scale circulation and convection. Despite recent progress in understanding MJO, comprehensive theory still missing, partly due to its complexity associated with moist physics nonlinearity.Here, we use normal mode decomposition reanalysis datasets show that can be understood...
Abstract It is well known that African easterly waves (AEWs) can develop into tropical cyclones. However, the processes leading to development are not understood. To this end, we examine a 38-year climatology of AEW tracks sorted developing (DAEWs) and strong non-developing (SNDAEWs) waves. Wave-centered composites for in eastern Atlantic (40°W-10°W, 5°S-30°N) west monsoon regions ( 10°W-20°E, reveal DAEWs occur over more humid background state both regions. The environment causes exhibit...
Abstract The representation of easterly waves (EWs) over the east Pacific Ocean (PEWs) in Coupled Model Intercomparison Project phase 6 (CMIP6) simulations is examined. Models are assessed based on their ability reproducing PEW‐related precipitation and its evolution. leading patterns reveal a large spread PEW structure amplitude. A comparison models with most realistic PEWs those unrealistically weak skill showed that more accurate effectively capture mean state EW thermodynamic structures...
Lowest events in Lake Titicaca’s water level (LTWL) significantly impact local ecosystems and the drinking supply Peru Bolivia. However, hydroclimatic mechanisms driving extreme lake-level lowstands remain poorly understood. To investigate these low events, we analyzed detrended monthly LTWL anomalies, sea surface temperature (SST) datasets covering period 1921–2023. ERA5 reanalysis covers 1940–2023. A multiple linear regression model was developed to compute excluding multidecadal residual...
Abstract Caribbean easterly waves (CEWs) propagate in an environment that is distinct from of other since it exhibits substantial westerly vertical wind shear. In spite this distinction, their structure, propagation and growth have not received much attention. A linear regression analysis reveals these systems exhibit features consistent with moisture modes are destabilized by moisture-vortex instability. They large fluctuations, weak temperature gradient (WTG) balance, moist static energy...
Abstract A normal mode decomposition of the dynamical structure quasi‐biennial oscillation (QBO) is presented in this article. It was found that QBO predominantly described by Rossby modes as well westward inertio‐gravity with a low meridional index. We show 2016 disruption accompanied an extreme amplitude event asymmetric zonal (with index 4) consisting largest 40 years. This component flow favors convergence eastward momentum equatorial region, controlling perturbations to QBO. The winds...
Abstract The governing thermodynamics of the Madden‐Julian Oscillation (MJO) is examined using sounding and reanalysis data. On basis four objective criteria, results suggest that MJO behaves like a moisture mode–a system whose governed by moisture–only over Indian Ocean. Over this basin, shows slow convective adjustment timescale, its zonal scale smaller, it exhibits propagation, allowing modes to exist. Elsewhere, faster‐propagating wavenumber 1–2 components are more prominent preventing...