D. L. Suhas

University of California, Berkeley | UCB · Department of Earth and Planetary Science

Transient atmospheric vortices called monsoon low pressure systems (LPS) generate a large fraction of total rainfall over South Asia and often produce extreme precipitation. Here, we assess the influence of these storms on the occurrence of disasters, using information from the Emergency Events Database (EM-DAT) that we geocoded and then associated...

Transient, synoptic-scale vortices produce a large fraction of total rainfall in most monsoon regions and are often associated with extreme precipitation. However, the mechanism of their amplification remains a topic of active research. For monsoon depressions, which are the most prominent synoptic-scale vortex in the Asian-Australian monsoon, rece...

Transient atmospheric vortices called monsoon low pressure systems (LPS) generate a large fraction of total rainfall over South Asia and often produce extreme precipitation. Here, we assess the influence of these storms on the occurrence of disasters, using information from the Emergency Events Database (EM-DAT) that we geocoded and then associated...

Turbulence and large‐scale waves in the tropical region are studied using the spherical shallow‐water equations. With mesoscale vorticity forcing, both moist and dry systems show an upscale transfer of kinetic energy that is dominated by rotational modes, scales as a power‐law with ‐5/3 exponent, requires eddy‐eddy interactions and ranges from the...

The steady and transient response of "dynamically" dry and moist atmospheres to uniform sea‐surface temperature (SST) is studied using an aquaplanet general circulation model (GCM). Specifically, the latent heat (Lv) of water vapor is varied, so that for small Lv, water substance is essentially a passive tracer from a dynamical point of view. Despi...

Turbulence and large-scale waves in the tropical region are studied using the spherical shallow water equations. With mesoscale vorticity forcing, both moist and dry systems show kinetic energy scaling that is dominated by rotational modes, has a -5/3 exponent. At larger planetary scales, the divergent component of the energy increases and we see a...

The steady and transient response of "dynamically" dry and moist atmospheres to uniform sea-surface temperature (SST) is studied. Specifically, the latent heat (Lv) of water vapor is varied, so that for small Lv, water substance is essentially a passive tracer from a dynamical point of view. Despite the lack of SST gradients, a general circulation...

The response of a spherical moist shallow water system to tropical imbalances in the presence of inhomogeneous saturation fields is examined. While the initial moist response is similar to the dry reference run, albeit with a reduced equivalent depth, the long time solution depends quite strikingly on the nature of the saturation field. For a satur...

The response of spherical moist and dry shallow water systems to localized tropical imbalances are examined. The nonlinear dry response consists of a combination of Rossby, Kelvin and mixed Rossby-Gravity waves, depending on the nature of the initial condition. Remarkably, most of the power in the nonlinear solution follows linear dispersion curves...

The response of the nonlinear shallow water equations (SWE) on a sphere to tropical vorticity forcing is examined with an emphasis on momentum fluxes and the emergence of a superrotating (SR) state. Fixing the radiative damping and momentum drag timescales to be of the order of a few days, a state of SR is shown to emerge under steady large-scale a...

Quasigeostrophic turbulence on a β-plane with a finite deformation radius is studied numerically, with particular emphasis on frequency and combined wavenumber-frequency domain analyses. Under suitable conditions, simulations with small-scale random forcing and large-scale drag exhibit a spontaneous formation of multiple zonal jets. The first hint...