Quality-Controlled Upper-Air Sounding Dataset for DYNAMO/CINDY/AMIE: Development and Corrections

2014 ◽  
Vol 31 (4) ◽  
pp. 741-764 ◽  
Author(s):  
Paul E. Ciesielski ◽  
Hungjui Yu ◽  
Richard H. Johnson ◽  
Kunio Yoneyama ◽  
Masaki Katsumata ◽  
...  
Keyword(s):  
Deep Convection ◽  
Precipitable Water ◽  
Eastern Africa ◽  
Operational Model ◽  
Heating Effects ◽  
Surface Data ◽  
Quality Checks ◽  
The Indian Ocean ◽  
High Vertical Resolution ◽  
The Tropics

Abstract The upper-air sounding network for Dynamics of the Madden–Julian Oscillation (DYNAMO) has provided an unprecedented set of observations for studying the MJO over the Indian Ocean, where coupling of this oscillation with deep convection first occurs. With 72 rawinsonde sites and dropsonde data from 13 aircraft missions, the sounding network covers the tropics from eastern Africa to the western Pacific. In total nearly 26 000 soundings were collected from this network during the experiment’s 6-month extended observing period (from October 2011 to March 2012). Slightly more than half of the soundings, collected from 33 sites, are at high vertical resolution. Rigorous post–field phase processing of the sonde data included several levels of quality checks and a variety of corrections that address a number of issues (e.g., daytime dry bias, baseline surface data errors, ship deck heating effects, and artificial dry spikes in slow-ascent soundings). Because of the importance of an accurate description of the moisture field in meeting the scientific goals of the experiment, particular attention is given to humidity correction and its validation. The humidity corrections, though small relative to some previous field campaigns, produced high-fidelity moisture analyses in which sonde precipitable water compared well with independent estimates. An assessment of operational model moisture analyses using corrected sonde data shows an overall good agreement with the exception at upper levels, where model moisture and clouds are more abundant than the sonde data would indicate.

Contribution of Tropical Cyclones to Global Very Deep Convection

2014 ◽  
Vol 27 (11) ◽  
pp. 4313-4336 ◽  
Author(s):  
Haiyan Jiang ◽  
Cheng Tao
Keyword(s):  
Tropical Cyclones ◽  
Deep Convection ◽  
Convective Available Potential Energy ◽  
Tropical Rainfall Measuring Mission ◽  
Precipitable Water ◽  
Moisture Exchange ◽  
Derived Properties ◽  
Trmm Precipitation ◽  
The Tropics ◽  
Heat And Moisture

Abstract Based on the 12-yr (1998–2009) Tropical Rainfall Measuring Mission (TRMM) precipitation feature (PF) database, both radar and infrared (IR) observations from TRMM are used to quantify the contribution of tropical cyclones (TCs) to very deep convection (VDC) in the tropics and to compare TRMM-derived properties of VDC in TCs and non-TCs. Using a radar-based definition, it is found that the contribution of TCs to total VDC in the tropics is not much higher than the contribution of TCs to total PFs. However, the area-based contribution of TCs to overshooting convection defined by IR is 13.3%, which is much higher than the 3.2% contribution of TCs to total PFs. This helps explain the contradictory results between previous radar-based and IR-based studies and indicates that TCs only contribute disproportionately large amount of overshooting convection containing mainly small ice particles that are barely detected by the TRMM radar. VDC in non-TCs over land has the highest maximum 30- and 40-dBZ height and the strongest ice-scattering signature derived from microwave 85- and 37-GHz observations, while VDC in TCs has the coldest minimum IR brightness temperature and largest overshooting distance and area. This suggests that convection is much more intense in non-TCs over land but is much deeper or colder in TCs. It is found that VDC in TCs usually has smaller environmental shear but larger total precipitable water and convective available potential energy than those in non-TCs. These findings offer evidence that TCs may contribute disproportionately to troposphere-to-stratosphere heat and moisture exchange.

scholarly journals Influence of Tropical Cyclones on Humidity Patterns over Southern Baja California, Mexico

2007 ◽  
Vol 135 (4) ◽  
pp. 1208-1224 ◽  
Author(s):  
Luis M. Farfán ◽  
Ira Fogel
Keyword(s):  
Tropical Cyclones ◽  
Gulf Of California ◽  
Large Scale ◽  
Baja California ◽  
Deep Convection ◽  
Precipitable Water ◽  
Operational Model ◽  
Western Mexico ◽  
Surface Station ◽  
Northwestern Mexico

Abstract The influence of tropical cyclone circulations in the distribution of humidity and convection over northwestern Mexico is investigated by analyzing circulations that developed in the eastern Pacific Ocean from 1 July to 21 September 2004. Documented cases having some impact over the Baja California Peninsula include Tropical Storm Blas (13–15 July), Hurricane Frank (23–25 August), Hurricane Howard (2–6 September), and Hurricane Javier (15–20 September). Datasets are derived from geostationary satellite imagery, upper-air and surface station observations, as well as an analysis from an operational model. Emphasis is given to circulations that moved within 800 km of the southern part of the peninsula. The distribution of precipitable water is used to identify distinct peaks during the approach of these circulations and deep convection that occurred for periods of several days over the southern peninsula and Gulf of California. Hurricane Howard is associated with a significant amount of precipitation, while Hurricane Javier made landfall across the central peninsula with a limited impact on the population in the area. An examination of the large-scale environment suggests that advection of humid air from the equatorial Pacific is an important element in sustaining tropical cyclones and convection off the coast of western Mexico.

scholarly journals The Amazon Dense GNSS Meteorological Network: A New Approach for Examining Water Vapor and Deep Convection Interactions in the Tropics

2015 ◽  
Vol 96 (12) ◽  
pp. 2151-2165 ◽  
Author(s):  
David K. Adams ◽  
Rui M. S. Fernandes ◽  
Kirk L. Holub ◽  
Seth I. Gutman ◽  
Henrique M. J. Barbosa ◽  
...  
Keyword(s):  
Water Vapor ◽  
Diurnal Cycle ◽  
Numerical Models ◽  
Deep Convection ◽  
Precipitable Water ◽  
Sea Breeze ◽  
Tropical Meteorology ◽  
Precipitable Water Vapor ◽  
Gnss Meteorology ◽  
The Tropics

Abstract The complex interactions between water vapor fields and deep atmospheric convection remain one of the outstanding problems in tropical meteorology. The lack of high spatial–temporal resolution, all-weather observations in the tropics has hampered progress. Numerical models have difficulties, for example, in representing the shallow-to-deep convective transition and the diurnal cycle of precipitation. Global Navigation Satellite System (GNSS) meteorology, which provides all-weather, high-frequency (5 min), precipitable water vapor estimates, can help. The Amazon Dense GNSS Meteorological Network experiment, the first of its kind in the tropics, was created with the aim of examining water vapor and deep convection relationships at the mesoscale. This innovative, Brazilian-led international experiment consisted of two mesoscale (100 km × 100 km) networks: 1) a 1-yr (April 2011–April 2012) campaign (20 GNSS meteorological sites) in and around Manaus and 2) a 6-week (June 2011) intensive campaign (15 GNSS meteorological sites) in and around Belem, the latter in collaboration with the Cloud Processes of the Main Precipitation Systems in Brazil: A Contribution to Cloud-Resolving Modeling and to the Global Precipitation Measurement (CHUVA) Project in Brazil. Results presented here from both networks focus on the diurnal cycle of precipitable water vapor associated with sea-breeze convection in Belem and seasonal and topographic influences in and around Manaus. Ultimately, these unique observations may serve to initialize, constrain, or validate precipitable water vapor in high-resolution models. These experiments also demonstrate that GNSS meteorology can expand into logistically difficult regions such as the Amazon. Other GNSS meteorology networks presently being constructed in the tropics are summarized.

scholarly journals DYAMOND: the DYnamics of the Atmospheric general circulation Modeled On Non-hydrostatic Domains

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Bjorn Stevens ◽  
Masaki Satoh ◽  
Ludovic Auger ◽  
Joachim Biercamp ◽  
Christopher S. Bretherton ◽  
...  
Keyword(s):  
General Circulation ◽  
Deep Convection ◽  
Precipitable Water ◽  
Energy Budgets ◽  
High Resolution Data ◽  
Convective Storms ◽  
Tropical Deep Convection ◽  
Basic Characteristics ◽  
Tropical Weather ◽  
The Tropics

Abstract A review of the experimental protocol and motivation for DYAMOND, the first intercomparison project of global storm-resolving models, is presented. Nine models submitted simulation output for a 40-day (1 August–10 September 2016) intercomparison period. Eight of these employed a tiling of the sphere that was uniformly less than 5 km. By resolving the transient dynamics of convective storms in the tropics, global storm-resolving models remove the need to parameterize tropical deep convection, providing a fundamentally more sound representation of the climate system and a more natural link to commensurately high-resolution data from satellite-borne sensors. The models and some basic characteristics of their output are described in more detail, as is the availability and planned use of this output for future scientific study. Tropically and zonally averaged energy budgets, precipitable water distributions, and precipitation from the model ensemble are evaluated, as is their representation of tropical cyclones and the predictability of column water vapor, the latter being important for tropical weather.

Evaluation of daily and diurnal signals of total precipitable water (TPW) over the Indian Ocean based on TMI retrieved 3-day composite estimates and radiosonde data

2007 ◽  
Vol 27 (6) ◽  
pp. 761-770 ◽  
Author(s):  
V. Sajith ◽  
Jimmy O. Adegoke ◽  
Santosh K. Raghavan ◽  
H. S. Ram Mohan ◽  
Vinod Kumar ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Precipitable Water ◽  
Radiosonde Data ◽  
Total Precipitable Water ◽  
The Indian Ocean

scholarly journals Africa and the wider world: creole communities in the Atlantic and Indian Oceans

Tempo ◽  
2017 ◽  
Vol 23 (3) ◽  
pp. 465-481
Author(s):  
Malyn Newitt
Keyword(s):  
Technology Transfer ◽  
Indian Ocean ◽  
World Economy ◽  
Sub Saharan Africa ◽  
Eastern Africa ◽  
Cultural Appropriation ◽  
The World ◽  
African Slaves ◽  
The Indian Ocean ◽  
Sub Saharan

Abstract: Portuguese creoles were instrumental in bringing sub-Saharan Africa into the intercontinental systems of the Atlantic and Indian Ocean. In the Atlantic Islands a distinctive creole culture emerged, made up of Christian emigrants from Portugal, Jewish exiles and African slaves. These creole polities offered a base for coastal traders and became politically influential in Africa - in Angola creating their own mainland state. Connecting the African interior with the world economy was largely on African terms and the lack of technology transfer meant that the economic gap between Africa and the rest of the world inexorably widened. African slaves in Latin America adapted to a society already creolised, often through adroit forms of cultural appropriation and synthesis. In eastern Africa Portuguese worked within existing creolised Islamic networks but the passage of their Indiamen through the Atlantic created close links between the Indian Ocean and Atlantic commercial systems.

scholarly journals An Evaluation of Precipitation Forecasts from Operational Models and Reanalyses Including Precipitation Variations Associated with MJO Activity

2010 ◽  
Vol 138 (12) ◽  
pp. 4542-4560 ◽  
Author(s):  
John E. Janowiak ◽  
Peter Bauer ◽  
Wanqiu Wang ◽  
Phillip A. Arkin ◽  
Jon Gottschalck
Keyword(s):  
Prediction Models ◽  
Coupled Model ◽  
Warm Season ◽  
Temporal Correlation ◽  
Operational Model ◽  
Temporal Correlations ◽  
Operational Models ◽  
Environmental Prediction ◽  
The Tropics ◽  
Model Precipitation

Abstract In this paper, the results of an examination of precipitation forecasts for 1–30-day leads from global models run at the European Centre for Medium-Range Weather Forecasts (ECMWF) and the National Centers for Environmental Prediction (NCEP) during November 2007–February 2008 are presented. The performance of the model precipitation forecasts are examined in global and regional contexts, and results of a case study of precipitation variations that are associated with a moderate to strong Madden–Julian oscillation (MJO) event are presented. The precipitation forecasts from the ECMWF and NCEP operational prediction models have nearly identical temporal correlation with observed precipitation at forecast leads from 2 to 9 days over the Northern Hemisphere during the cool season, despite the higher resolution of the ECMWF operational model, while the ECMWF operational model forecasts are slightly better in the tropics and the Southern Hemisphere during the warm season. The ECMWF Re-Analysis Interim (ERA-Interim) precipitation forecasts perform only slightly worse than the NCEP operational model, while NCEP’s Climate Forecast System low-resolution coupled model forecasts perform the worst among the four models. In terms of bias, the ECMWF operational model performs the best among the four model forecasts that were examined, particularly with respect to the ITCZ regions in both the Atlantic and Pacific. Local temporal correlations that were computed on daily precipitation totals for day-2 forecasts against observations indicate that the operational models at ECMWF and NCEP perform the best during the 4-month study period, and that all of the models have low to insignificant correlations over land and over much of the tropics. They perform the best in subtropical and extratropical oceanic regions. Also presented are results that show that striking improvements have been made over the past two decades in the ability of the models to represent precipitation variations that are associated with MJO. The model precipitation forecasts exhibit the ability to characterize the evolution of precipitation variations during a moderate–strong period of MJO conditions for forecast leads as long as 10 days.

scholarly journals Coffee: An Indian Ocean Perspective

2016 ◽  
Vol 11 (2) ◽  
pp. 61-81
Author(s):  
Shane J. Barter
Keyword(s):  
Indian Ocean ◽  
South Asia ◽  
Latin American ◽  
Eastern Africa ◽  
Coffee Production ◽  
Production And Consumption ◽  
History Of ◽  
Coffee Farmers ◽  
The Indian Ocean ◽  
Indian Ocean World

Abstract Studies of coffee production and consumption are dominated by emphases on Latin American production and American consumption. This paper challenges the Atlantic perspective, demanding an equal emphasis on the Indian Ocean world of Eastern Africa, the Middle East, South Asia, and Southeast Asia. A geographical approach to historical as well as contemporary patterns of coffee production and consumption provides an opportunity to rethink the nature of coffee as a global commodity. The Indian Ocean world has a much deeper history of coffee, and in recent decades, has witnessed a resurgence in production. The nature of this production is distinct, providing an opportunity to rethink dependency theories. Coffee in the Indian Ocean world is more likely to be produced by smallholders, countries are less likely to be economically dependent on coffee, farmers are more likely to harvest polycultures, and countries represent both consumers and producers. A balanced emphasis of Atlantic and Indian Ocean worlds allows us to better understand coffee production and consumption, together telling a more balanced, global story of this important commodity.

scholarly journals Land–atmosphere interactions in the tropics

2019 ◽  
Author(s):  
Pierre Gentine ◽  
Adam Massmann ◽  
Benjamin R. Lintner ◽  
Sayed Hamed Alemohammad ◽  
Rong Fu ◽  
...  
Keyword(s):  
Land Surface ◽  
Deep Convection ◽  
Lower Troposphere ◽  
Surface Fluxes ◽  
Surface Radiation ◽  
Spatial And Temporal Scales ◽  
Wide Range ◽  
Shallow Clouds ◽  
The Tropics ◽  
The Impact

Abstract. The continental tropics play a leading role in the terrestrial water and carbon cycles. Land–atmosphere interactions are integral in the regulation of surface energy, water and carbon fluxes across multiple spatial and temporal scales over tropical continents. We review here some of the important characteristics of tropical continental climates and how land–atmosphere interactions regulate them. Along with a wide range of climates, the tropics manifest a diverse array of land–atmosphere interactions. Broadly speaking, in tropical rainforests, light and energy are typically more limiting than precipitation and water supply for photosynthesis and evapotranspiration; whereas in savanna and semi-arid regions water is the critical regulator of surface fluxes and land–atmosphere interactions. We discuss the impact of the land surface, how it affects shallow clouds and how these clouds can feedback to the surface by modulating surface radiation. Some results from recent research suggest that shallow clouds may be especially critical to land–atmosphere interactions as these regulate the energy budget and moisture transport to the lower troposphere, which in turn affects deep convection. On the other hand, the impact of land surface conditions on deep convection appear to occur over larger, non-local, scales and might be critically affected by transitional regions between the climatologically dry and wet tropics.

scholarly journals Triggering the Indian Ocean Dipole from the Southern Hemisphere

2021 ◽  
Author(s):  
Lian-Yi Zhang ◽  
Yan Du ◽  
Wenju Cai ◽  
Zesheng Chen ◽  
Tomoki Tozuka ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Southern Hemisphere ◽  
Indian Ocean Dipole ◽  
Southern Oscillation ◽  
Southern Annular Mode ◽  
Triggering Mechanism ◽  
Phase Development ◽  
The Indian Ocean ◽  
High System ◽  
The Tropics

<p>This study identifies a new triggering mechanism of the Indian Ocean Dipole (IOD) from the Southern Hemisphere. This mechanism is independent from the El Niño/Southern Oscillation (ENSO) and tends to induce the IOD before its canonical peak season. The joint effects of this mechanism and ENSO may explain different lifetimes and strengths of the IOD. During its positive phase, development of sea surface temperature cold anomalies commences in the southern Indian Ocean, accompanied by an anomalous subtropical high system and anomalous southeasterly winds. The eastward movement of these anomalies enhances the monsoon off Sumatra-Java during May-August, leading to an early positive IOD onset. The pressure variability in the subtropical area is related with the Southern Annular Mode, suggesting a teleconnection between high-latitude and mid-latitude climate that can further affect the tropics. To include the subtropical signals may help model prediction of the IOD event.</p>

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