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A theory for the response of tropical moist convection to mechanical orographic forcing

Spatial patterns of tropical rainfall are strongly influenced by mountains. Although theories for precipitation induced by convectively stable upslope ascent exist for the midlatitudes, these do not represent the interaction of moist convection with …

Mechanical forcing of the North American monsoon by orography

A band of intense rainfall extends more than 1,000 km along Mexico's west coast during northern hemisphere summer, constituting the core of the North American monsoon. As in other tropical monsoons, this rainfall maximum is commonly thought to be …

Upper-tropospheric troughs and North American monsoon rainfall in a long-term track dataset

The North American monsoon is frequently affected by transient, propagating upper tropospheric vorticity anomalies. Sometimes called Tropical Upper-Tropospheric Troughs (TUTTs), these features have been claimed to episodically enhance monsoon …

Radiative feedbacks on land surface change and associated tropical precipitation shifts

Changes in land surface albedo and land surface evaporation modulate the atmospheric energy budget by changing temperatures, water vapor, clouds, snow and ice cover, and the partitioning of surface energy fluxes. Here idealized perturbations to land …

Explaining globally inhomogeneous future changes in monsoons using simple moist energy diagnostics

This study examines the annual cycle of monsoon precipitation simulated by models from the Coupled Model Intercomparison Project phase 6 (CMIP6), then uses moist energy diagnostics to explain globally inhomogeneous projected future changes. Rainy …

The influence of surface heat fluxes on the growth of idealized monsoon depressions

This study explores the effect of surface sensible and latent heat fluxes on monsoon depressions using a series of idealized convection-permitting simulations. Each experiment is initialized with a small amplitude wave that is allowed to grow within …

The globally coherent pattern of autumn monsoon precipitation

Over most tropical land areas, the annual peak in precipitation occurs during summer, associated with the local monsoon circulation. However, in some coastal regions in the tropics the bulk of annual precipitation occurs in autumn, after the …

Evolution of idealized vortices in monsoon-like shears: application to monsoon depressions

This study examines processes fundamental to the development of South Asian monsoon depressions using an array of integrations of an idealized convection-permitting numerical model. In each integration, a wave of initially small amplitude is …

Response of extreme precipitation to uniform surface warming in quasi-global aquaplanet simulations at high resolution

Projections of precipitation extremes in simulations with global climate models are very uncertain in the tropics, in part because of the use of parameterizations of deep convection and model deficiencies in simulating convective organization. Here …

Influence of intraseasonal variability on the development of monsoon depressions

Previous studies showed that the activity of monsoon low pressure systems (LPS), which produce a large fraction of the South Asian monsoon’s total rainfall, is modulated by intraseasonal variability. Using satellite-derived products and atmospheric …