Inter-hemispheric and inter-zonal moisture transports and monsoon regimes

2016 ◽  
Vol 36 (15) ◽  
pp. 4705-4722 ◽  
Author(s):  
Claudia Priscila Wanzeler da Costa ◽  
Prakki Satyamurty
Keyword(s):  
Moisture Transports

scholarly journals Supplementary material to "Impact of poleward heat and moisture transports on Arctic clouds and climate simulation"

2019 ◽  
Author(s):  
Eun-Hyuk Baek ◽  
Joo-Hong Kim ◽  
Sungsu Park ◽  
Baek-Min Kim ◽  
Jee-Hoon Jeong
Keyword(s):  
Climate Simulation ◽  
Arctic Clouds ◽  
Supplementary Material ◽  
Heat And Moisture ◽  
Moisture Transports

scholarly journals Decadal changes of wintertime poleward heat and moisture transport associated with the amplified Arctic warming

2021 ◽  
Author(s):  
Xiaozhuo Sang ◽  
Xiu-Qun Yang ◽  
Lingfeng Tao ◽  
Jiabei Fang ◽  
Xuguang Sun
Keyword(s):  
Heat Transport ◽  
Moisture Transport ◽  
Stationary Wave ◽  
The Arctic ◽  
Stationary Waves ◽  
High Latitudes ◽  
Arctic Warming ◽  
Poleward Heat Transport ◽  
Heat And Moisture ◽  
Moisture Transports

Abstract The Arctic warming, especially during winter, has been almost twice as large as the global average since the late 1990s, which is known as the Arctic amplification. Yet linkage between the amplified Arctic warming and the midlatitude change is still under debate. This study examines the decadal changes of wintertime poleward heat and moisture transports between two 18-yr epochs (1999–2016 and 1981–1998) with five atmospheric reanalyses. It is found that the wintertime Arctic warming induces an amplification of the high latitude stationary wave component of zonal wavenumber one but a weakening of the wavenumber two. These stationary wave changes enhance poleward heat and moisture transports, which are conducive to further Arctic warming and moistening, acting as a positive feedback onto the Arctic warming. Meanwhile, the Arctic warming reduces atmospheric baroclinicity and thus weakens synoptic eddy activities in the high latitudes. The decreased transient eddy activities reduce poleward heat and moisture transports, which decrease the Arctic temperature and moisture, acting as a negative feedback onto the Arctic warming. The total poleward heat transport contributes little to the Arctic warming, since the increased poleward heat transport by stationary waves is nearly canceled by the decreased transport by transient eddies. However, the total poleward moisture transport increases over most areas of the high latitudes that is dominated by the increased transport by stationary waves, which provides a significant net positive feedback onto the Arctic warming and moistening. Such a poleward moisture transport feedback may be particularly crucial to the amplified Arctic warming during winter when the ice-albedo feedback vanishes.

Amazon Coastal Squall Lines. Part II: Heat and Moisture Transports

1994 ◽  
Vol 122 (4) ◽  
pp. 623-635 ◽  
Author(s):  
Steven Greco ◽  
John Scala ◽  
Jeffrey Halverson ◽  
Harold L. Massie ◽  
Wei-Kuo Tao ◽  
...  
Keyword(s):  
Squall Lines ◽  
Heat And Moisture ◽  
Moisture Transports

scholarly journals Annual and Seasonal Precipitation and Their Extremes over the Tibetan Plateau and Its Surroundings in 1963–2015

Atmosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 620
Author(s):  
Jin Ding ◽  
Lan Cuo ◽  
Yongxin Zhang ◽  
Cunjie Zhang ◽  
Liqiao Liang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Extreme Precipitation ◽  
Daily Precipitation ◽  
The Tibetan Plateau ◽  
Opposite Pattern ◽  
Westerly Jet ◽  
Extreme Precipitation Events ◽  
Daily Precipitation Data ◽  
Moisture Transports ◽  
Precipitation Events

Based on daily precipitation data from 115 climate stations, seasonal and annual precipitation and their extremes over the Tibetan Plateau and its surroundings (TPS) in 1963–2015 are investigated. There exists a clear southeast-northwest gradient in precipitation and extreme daily precipitation but an opposite pattern for the consecutive dry days (CDDs). The wet southeast is trending dry while the dry center and northwest are trending wet in 1963–2015. Correspondingly, there is a drying tendency over the wet basins in the southeast and a wetting tendency over the dry and semi-dry basins in the center and northwest in summer, which will affect the water resources in the corresponding areas. The increase (decrease) in precipitation tends to correspond to the increase (decrease) in maximum daily precipitation but the decrease (increase) in CDDs. Extreme precipitation events with 20-year, 50-year, 100-year, and 200-year recurrence occurred frequently in the past decades especially in the 1980s. The greatest extreme precipitation events tend to occur after the late 1990s and in the southeastern TPS. The ERA5 reanalysis and climate system indices reveal that (1) decreased moisture transports to the southeast in summer due to the weakening of the summer monsoons and the East Asian westerly jet; (2) increased moisture transports to the center in winter due to the strengthening of the winter westerly jet and north Atlantic oscillation; and (3) decreased instability over the southeast thus suppressing precipitation and increased instability over the northwest thus promoting precipitation. All these are conducive to the drying trends in the southeast and the wetting trends in the center.

scholarly journals Mechanisms Linking Global 5-Day Waves to Tropical Convection

2017 ◽  
Vol 74 (11) ◽  
pp. 3679-3702 ◽  
Author(s):  
Malcolm J. King ◽  
Matthew C. Wheeler ◽  
Todd P. Lane
Keyword(s):  
Amazon Basin ◽  
Tropical Convection ◽  
Congo Basin ◽  
Gulf Of Guinea ◽  
Atmospheric Moisture ◽  
Local Climate ◽  
Low Level ◽  
The Andes ◽  
Convergence Zones ◽  
Moisture Transports

Abstract Reanalysis data and satellite-derived rainfall measurements are examined to determine possible mechanisms linking the “5 day” Rossby–Haurwitz wave to localized variations of tropical convection. The mechanisms in all regions rely on the modulation of zonal winds near the equator by the wave, but the nature of these mechanisms depends strongly on local topography and local climate. In the upper Amazon basin, the wave modulates the strength of prevailing easterlies and thus the upslope flow and associated convection on the eastern edge of the Andes. Similar modulation of upslope flow is involved off the Panamanian and Colombian Pacific coasts, but the deflection and confluence of low-level wind in the presence of the Andes and moisture transports across the Andes from the Amazon basin are also factors. Similar deflection and confluence of winds around and through the Maritime Continent lead to low-level divergence and convection anomalies over the eastern Indian Ocean. Anomalous moisture transports from the Congo basin to the eastern and northeastern Gulf of Guinea due to the wave affect atmospheric moisture over the Gulf of Guinea and thus convection in the region. Over oceanic convergence zones, modulations of the prevailing winds by the wave affect the overall wind magnitude, changing evaporation from the ocean surface and atmospheric moisture. Most of these mechanisms arise from the nonuniform nature of Earth’s surface and suggest that other external Rossby–Haurwitz waves may have similar interactions with convection.

The roles of moisture transports in intraseasonal precipitation during the preflood season over South China

2019 ◽  
Vol 40 (4) ◽  
pp. 2239-2252
Author(s):  
Qu‐cheng Chu ◽  
Qi‐guang Wang ◽  
Guo‐lin Feng
Keyword(s):  
South China ◽  
Moisture Transports

Global Thermohaline Circulation. Part II: Sensitivity with Interactive Atmospheric Transports

1999 ◽  
Vol 12 (1) ◽  
pp. 83-91 ◽  
Author(s):  
Xiaoli Wang ◽  
Peter H. Stone ◽  
Jochem Marotzke
Keyword(s):  
Southern Hemisphere ◽  
General Circulation ◽  
Large Scale ◽  
Thermohaline Circulation ◽  
Circulation Model ◽  
Ocean Atmosphere ◽  
Heat And Moisture ◽  
Sst Gradient ◽  
Moisture Transports ◽  
Flux Adjustment

Abstract A hybrid coupled ocean–atmosphere model is used to investigate the stability of the thermohaline circulation (THC) to an increase in the surface freshwater forcing in the presence of interactive meridional transports in the atmosphere. The ocean component is the idealized global general circulation model used in Part I. The atmospheric model assumes fixed latitudinal structure of the heat and moisture transports, and the amplitudes are calculated separately for each hemisphere from the large-scale sea surface temperature (SST) and SST gradient, using parameterizations based on baroclinic stability theory. The ocean–atmosphere heat and freshwater exchanges are calculated as residuals of the steady-state atmospheric budgets. Owing to the ocean component’s weak heat transport, the model has too strong a meridional SST gradient when driven with observed atmospheric meridional transports. When the latter are made interactive, the conveyor belt circulation collapses. A flux adjustment is introduced in which the efficiency of the atmospheric transports is lowered to match the too low efficiency of the ocean component. The feedbacks between the THC and both the atmospheric heat and moisture transports are positive, whether atmospheric transports are interactive in the Northern Hemisphere, the Southern Hemisphere, or both. However, the feedbacks operate differently in the Northern and Southern Hemispheres, because the Pacific THC dominates in the Southern Hemisphere, and deep water formation in the two hemispheres is negatively correlated. The feedbacks in the two hemispheres do not necessarily reinforce each other because they have opposite effects on low-latitude temperatures. The model is qualitatively similar in stability to one with conventional “additive” flux adjustment, but quantitatively more stable.

scholarly journals Atmospheric Moisture Transports from Ocean to Land and Global Energy Flows in Reanalyses

2011 ◽  
Vol 24 (18) ◽  
pp. 4907-4924 ◽  
Author(s):  
Kevin E. Trenberth ◽  
John T. Fasullo ◽  
Jessica Mackaro
Keyword(s):  
Large Scale ◽  
Climate Model ◽  
Hydrological Cycle ◽  
Surface Fluxes ◽  
Return Flow ◽  
Freshwater Flux ◽  
Atmospheric Moisture ◽  
Global Energy ◽  
Model Based ◽  
Moisture Transports

Abstract An assessment is made of the global energy and hydrological cycles from eight current atmospheric reanalyses and their depiction of changes over time. A brief evaluation of the water and energy cycles in the latest version of the NCAR climate model referred to as CCSM4 is also given. The focus is on the mean ocean, land, and global precipitation P; the corresponding evaporation E; their difference corresponding to the surface freshwater flux E–P; and the vertically integrated atmospheric moisture transports. Using the model-based P and E, the time- and area-average E–P for the oceans, P–E for land, and the moisture transport from ocean to land should all be identical but are not close in most reanalyses, and often differ significantly from observational estimates of the surface return flow based on net river discharge into the oceans. Their differences reveal outstanding issues with atmospheric models and their biases, which are manifested as analysis increments in the reanalyses. The NCAR CCSM4, along with most reanalysis models, the exception being MERRA, has too-intense water cycling (P and E) over the ocean although ocean-to-land transports are very close to observed. Precipitation from reanalyses that assimilate moisture from satellite observations exhibits large changes identified with the changes in the observing system, as new and improved temperature and water vapor channels are assimilated and, while P improves after about 2002, E–P does not. Discrepancies among hydrological cycle components arise from analysis increments that can add or subtract moisture. The large-scale moisture budget divergences are more stable in time and similar across reanalyses than model-based estimates of E–P. Results are consistent with the view that recycling of moisture is too large in most models and the lifetime of moisture is too short. For the energy cycle, most reanalyses have spurious imbalances of ~10 W m−2 within the atmosphere, and ~5–10 W m−2 in net fluxes into the surface and to space. Major improvements are needed in model treatment and assimilation of moisture, and surface fluxes from reanalyses should only be used with great caution.

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