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Brian Mapes  - - - 
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Teddy Allen

4 shared publications

The International Institute for Climate and Society, Earth Institute; Columbia University; Palisades NY USA

25
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Publication Record
Distribution of Articles published per year 
(2003 - 2019)
Total number of journals
published in
 
11
 
Publications See all
Article 0 Reads 0 Citations Estimating convection’s moisture sensitivity: an observation-model synthesis using AMIE-DYNAMO field data Brian Mapes, Arunchandra S. Chandra, Zhiming Kuang, Siwon So... Published: 19 March 2019
Journal of the Atmospheric Sciences, doi: 10.1175/jas-d-18-0127.1
DOI See at publisher website
BOOK-CHAPTER 3 Reads 0 Citations Cumulus Friction in the Asian Monsoon of a Global Model with 7 km Mesh Suvarchal K. Cheedela, Brian E. Mapes Published: 01 February 2019
Perspectives on Atmospheric Sciences, doi: 10.1007/978-981-13-3396-5_10
DOI See at publisher website ABS Show/hide abstract
Vertical transport of horizontal momentum by convective eddies (CMT) in the 7–400 km size range is examined comprehensively in data from the GEOS-5 Nature Run (G5NR), a 2-year global simulation with a 7 km horizontal mesh. This diagnosis is possible because NASA offers a coarse-grained dataset of the quadratic flux terms wu and wv in addition to the model velocity variables u, v, w. We assess the time tendency of large-scale vertically integrated shear kinetic energy (SKE) due to CMT. Negative values of a few tenths of \(1W m^{-2}\) prevail on average over warm tropical oceans, indicating that explicit convection on these scales exerts a viscous or frictional or downgradient transport effect on wind shear. However, positive as well as negative values do occur locally, based on spatial correlations u\(^\prime \)w\(^\prime \) and v\(^\prime \)w\(^\prime \) in the arrangement (“organization”) of convective motions. In the Asian monsoon, where convection and shear are both strong, the viscosity can be characterized by a regression coefficient with values of about 5% cm\(^{-1}\), meaning that convection which yields 1 cm of precipitation decrements SKE by about 5%. Adjustment of balanced monsoon flow to such a viscous effect implies adiabatic ascent to the north of existing convection, a mechanism that may be relevant to northward-propagating large-scale variability.
Article 0 Reads 0 Citations Shape of Atlantic Tropical Cyclone Tracks and the Indian Monsoon Patrick Kelly, L. Ruby Leung, Karthik Balaguru, Wenwei Xu, B... Published: 10 October 2018
Geophysical Research Letters, doi: 10.1029/2018gl080098
DOI See at publisher website
Article 1 Read 1 Citation Effects of a Simple Convective Organization Scheme in a Two-Plume GCM Baohua Chen, Brian E. Mapes Published: 30 March 2018
Journal of Advances in Modeling Earth Systems, doi: 10.1002/2017ms001106
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A set of experiments is described with the Community Atmosphere Model (CAM5) using a two-plume convection scheme. To represent the differences of organized convection from General Circulation Model (GCM) assumptions of isolated plumes in uniform environments, a dimensionless prognostic “organization” tracer Ω is invoked to lend the second plume a buoyancy advantage relative to the first, as described in Mapes and Neale (2011). When low-entrainment plumes are unconditionally available (Ω = 1 everywhere), deep convection occurs too easily, with consequences including premature (upstream) rainfall in inflows to the deep tropics, excessive convective vs. large-scale rainfall, poor relationships to the vapor field, stable bias in the mean state, weak and poor tropical variability, and midday peak in diurnal rainfall over land. Some of these are shown to also be characteristic of CAM4 with its separated deep and shallow convection schemes. When low-entrainment plumes are forbidden by setting Ω = 0 everywhere, some opposite problems can be discerned. In between those extreme cases, an interactive Ω driven by the evaporation of precipitation acts as a local positive feedback loop, concentrating deep convection: In areas of little recent rain, only highly entraining plumes can occur, unfavorable for rain production. This tunable mechanism steadily increases precipitation variance in both space and time, as illustrated here with maps, time-longitude series, and spectra, while avoiding some mean state biases as illustrated with process-oriented diagnostics such as conserved variable profiles and vapor-binned precipitation curves.
Article 3 Reads 0 Citations The Meandering Margin of the Meteorological Moist Tropics Brian E. Mapes, Eui Seok Chung, Walter M. Hannah, Hirohiko M... Published: 28 January 2018
Geophysical Research Letters, doi: 10.1002/2017gl076440
DOI See at publisher website
PROCEEDINGS-ARTICLE 8 Reads 0 Citations The late spring Caribbean rain-belt: climatology and dynamics Teddy Allen, Brian Mapes Published: 11 November 2017
Proceedings of First International Electronic Conference on the Hydrological Cycle, doi: 10.3390/chycle-2017-04881
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This study examines the dynamics of late spring rainfall (the Early Rainy Season, ERS) in the Caribbean region, in hopes of identifying mechanistic-based predictors for low-frequency climate modulations of the system. The subtropical Caribbean rain-belt develops in May as seasonal warming proceeds. By July, the rain-belt retreats north apparently following the westerlies and their vigorous synoptic disturbances. Daily climatology data suggest a physical definition of the Caribbean ERS as mid-May to mid-late June. Based on an examination of daily loops for several seasons, we hypothesize that rainfall occurs quasi-randomly throughout tongues of air with sufficiently high (above 45–50 mm) precipitable water (PW). These moist airmasses are brought north from the deep tropics by low-level southerlies, and typically bent over into SW-NE bands by latitudinal shear of the westerlies. The low-level flow that transports PW tongues is partly induced by upper-level synoptic disturbances in the westerlies, but also involves the gentle persistent flow around a geographically anchored Panama Low. While forced ascent is sometimes active ahead of these upper-level troughs, convective and mesoscale processes can produce rain wherever PW is sufficient. In summary, we hypothesize that rainfall hinges largely on the Lagrangian statistics of moist air tongues. Comparison is drawn between the Caribbean rain-belt and its East Asian counterpart (Meiyu-Baiu), and other mechanisms and diagnostics from that literature are discussed. Statistical prediction exercises, based on mechanistically chosen predictors, could both test hypotheses and aid local agricultural interests in the region.
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