Climate projections in fine resolution downscaling over South America: trends and classification of cyclonic systems

2020 ◽  
Author(s):  
Rosmeri Porfírio da Rocha ◽  
Michelle Simões Reboita ◽  
Natália Machado Crespo ◽  
Eduardo Marcos de Jesus ◽  
Andressa Andrade Cardoso ◽  
...  
Keyword(s):  
South America ◽  
Atlantic Ocean ◽  
South Atlantic ◽  
South Atlantic Ocean ◽  
Eastern Coast ◽  
Cmip5 Models ◽  
Climate Projections ◽  
Near Surface ◽  
Fine Resolution ◽  
The Impact

<p>Cyclones developing in eastern coast of South America impact weather and control the climate in most parts of the continent as well as over the South Atlantic Ocean. Current knowledge of these cyclones shows that they can have different thermal and dynamic structures along their lifecycles being classified as tropical, subtropical or extratropical. Cyclones occurring over the sea generate intense near-surface winds with major impacts on human activities and ecosystems. Given this context, we are producing fine resolution (~25 km) dynamic downscaling with RegCM4 to investigate the climatic trends of the different phases of cyclones over the southwest South Atlantic Ocean. Special emphasis will be given on the contribution of subtropical cyclones causing extreme events (rainfall and wind) in eastern Brazil. The simulations cover South America and wider area of South Atlantic Ocean. For evaluation simulation RegCM4 is forced by ERA-Interim reanalysis, while for the projections by CMIP5 models under RCP4.5 and RCP8.5 scenarios. Cyclones are tracked using an algorithm based on cyclonic relative vorticity. In this study we present the climatology of all cyclones provided by the ERA-Interim evaluation simulation in the period 1979-2015. Basically, we discuss the ability of fine resolution simulation in reproducing the main cyclogenetic areas over the continent, seasonality and interannual variability of cyclones. Comparisons with previous simulations allow discussing the impact of fine resolution downscaling on the climatological features of all cyclones and their classification in South America domain.    </p>

scholarly journals Modulation of Midtropospheric CO2 by the South Atlantic Walker Circulation*

2015 ◽  
Vol 72 (6) ◽  
pp. 2241-2247 ◽  
Author(s):  
Xun Jiang ◽  
Edward T. Olsen ◽  
Thomas S. Pagano ◽  
Hui Su ◽  
Yuk L. Yung
Keyword(s):  
South America ◽  
Atlantic Ocean ◽  
Large Scale ◽  
Climate Models ◽  
Walker Circulation ◽  
South Atlantic ◽  
South Atlantic Ocean ◽  
Strong Impact ◽  
The South ◽  
Near Surface

Abstract Midtropospheric CO2 data from the Atmospheric Infrared Sounder (AIRS) are used in this study to explore the variability of CO2 over the South Atlantic Ocean. It was found that the area-averaged CO2 over the South Atlantic Ocean is less than that over South America by about 1 ppm during December–March. This CO2 contrast is due to the large-scale vertical circulation over this region. During December–March, there is sinking motion over the South Atlantic Ocean. The sinking motion brings high-altitude air with a slightly lower concentration of CO2 to the midtroposphere. Meanwhile, air rising over South America brings near-surface air with a higher concentration of CO2 to the midtroposphere. As a result, the AIRS midtropospheric CO2 concentration is lower over the South Atlantic Ocean than over South America during December–March. The detrended AIRS midtropospheric CO2 difference correlates well with the inverted and detrended 400-hPa vertical pressure velocity difference between the South Atlantic and South America. Results obtained from this study demonstrate the strong impact of large-scale circulation on the vertical distribution of CO2 in the free troposphere and suggest that midtropospheric CO2 measurements can be used as an innovative observational constraint on the simulation of large-scale circulations in climate models.

The impact of mesoscale eddies on the phytoplankton community in the South Atlantic Ocean: HPLC-CHEMTAX approach

2019 ◽  
Vol 144 ◽  
pp. 154-165 ◽  
Author(s):  
Andréa da Consolação de Oliveira Carvalho ◽  
Carlos Rafael B. Mendes ◽  
Rodrigo Kerr ◽  
José Luiz Lima de Azevedo ◽  
Felippe Galdino ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Phytoplankton Community ◽  
Mesoscale Eddies ◽  
South Atlantic ◽  
South Atlantic Ocean ◽  
The South ◽  
The Impact

scholarly journals The impact of air–sea coupling and ocean biases on the seasonal cycle of southern West African precipitation

2019 ◽  
Vol 53 (11) ◽  
pp. 7027-7044
Author(s):  
Caroline M. Wainwright ◽  
Linda C. Hirons ◽  
Nicholas P. Klingaman ◽  
Richard P. Allan ◽  
Emily Black ◽  
...  
Keyword(s):  
West Africa ◽  
Atlantic Ocean ◽  
Crop Yields ◽  
Coupled Model ◽  
Dry Season ◽  
Global Ocean ◽  
Cmip5 Models ◽  
Rainfall Regime ◽  
Climate Projections ◽  
The Impact

Abstract The biannual seasonal rainfall regime over the southern part of West Africa is characterised by two wet seasons, separated by the ‘Little Dry Season’ in July–August. Lower rainfall totals during this intervening dry season may be detrimental for crop yields over a region with a dense population that depends on agricultural output. Coupled Model Intercomparison Project Phase 5 (CMIP5) models do not correctly capture this seasonal regime, and instead generate a single wet season, peaking at the observed timing of the Little Dry Season. Hence, the realism of future climate projections over this region is questionable. Here, the representation of the Little Dry Season in coupled model simulations is investigated, to elucidate factors leading to this misrepresentation. The Global Ocean Mixed Layer configuration of the Met Office Unified Model is particularly useful for exploring this misrepresentation, as it enables separating the effects of coupled model ocean biases in different ocean basins while maintaining air–sea coupling. Atlantic Ocean SST biases cause the incorrect seasonal regime over southern West Africa. Upper level descent in August reduces ascent along the coastline, which is associated with the observed reduction in rainfall during the Little Dry Season. When coupled model Atlantic Ocean biases are introduced, ascent over the coastline is deeper and rainfall totals are higher during July–August. Hence, this study indicates detrimental impacts introduced by Atlantic Ocean biases, and highlights an area of model development required for production of meaningful climate change projections over the West Africa region.

Determining the range for CMIP climate projections for Europe using a sub-selected model ensemble based on key model performance indicators and key regional physical processes.

2020 ◽  
Author(s):  
Tamzin Palmer ◽  
Carol Mc Sweeney ◽  
Ben Booth
Keyword(s):  
Surface Temperature ◽  
Performance Indicators ◽  
Model Performance ◽  
Cmip5 Models ◽  
Climate Projections ◽  
Physical Processes ◽  
Near Surface ◽  
European Area ◽  
The Uk ◽  
The Impact

<p>An alternative approach to constraining climate projections based on a probabilistic approach with observational constraints, is to select a subset of models from the ensemble based on their ability to represent key physical processes, along with some indicators of model performance. The method that is presented here is based on the assumption that if a model is unable to reproduce the key factors important for determining the regional climate, the projections from this model are not considered reliable. The projection range for CMIP5 for the three EUCP European regions is assessed using two different subsampled model ensembles.</p><p>The first sub-sampling method presented uses the approach of Mc Sweeney et al. (2015), which assessed the models based on their performance for the UK climate. Each model in the CMIP5 ensemble (where data is available), is firstly assessed against these key performance indicators and poor performers eliminated from the selection. Several models also share large portions of code and therefore have similar errors and projections, Sanderson et al 2015a and 2015b quantifies these similarities. This analysis was used identify ‘near-neighbours’ and further reduce the selection. The applicability of a sub-selection of models based on their performance for the UK climate is assessed for the wider European area and found to reduce the projected range for the Northern European Area (NEU), for precipitation and near surface temperature considerably. The impact on the projected ranges for the Central European Area (CEU) and the Mediterranean (MED) was not as large, suggesting that a different set of physical processes are of primary importance for these regions.</p><p>To further investigate the effect of subsampling based on physical processes, a subset of CMIP5 models identified by the approach of Vogel et al. (2018) has been applied for the EUCP European areas. Vogel et al. (2018) looked at the ability of the CMIP5 models to reproduce the correlation between the hottest day of the year and precipitation within the same range as that found in the observations. This approach is designed to subsample the ensemble based on the ability of the model to represent soil moisture feedback processes with the atmosphere. It is thought that these processes are likely to be increasingly important for determining the projected climate in the CEU and MED regions.  </p><p>Finally, the projection range for the CMIP6 ensemble in the EUCP regions for precipitation and the near surface temperature will be presented and compared with those for CMIP5.</p>

scholarly journals Comparison of near-surface mean and eddy flows from two numerical models of the South Atlantic Ocean

2001 ◽  
Vol 106 (C8) ◽  
pp. 16857-16867 ◽  
Author(s):  
Thierry Penduff ◽  
Bernard Barnier ◽  
Karine Béranger ◽  
Jacques Verron
Keyword(s):  
Atlantic Ocean ◽  
Numerical Models ◽  
South Atlantic ◽  
South Atlantic Ocean ◽  
The South ◽  
Near Surface

Assessing levels of POPs in air over the South Atlantic Ocean off the coast of South America

2016 ◽  
Vol 571 ◽  
pp. 172-177 ◽  
Author(s):  
César N. Pegoraro ◽  
Tom Harner ◽  
Ky Su ◽  
Malisa S. Chiappero
Keyword(s):  
South America ◽  
Atlantic Ocean ◽  
South Atlantic ◽  
South Atlantic Ocean ◽  
The South

scholarly journals Rapid increase in Asian bottles in the South Atlantic Ocean indicates major debris inputs from ships

2019 ◽  
Vol 116 (42) ◽  
pp. 20892-20897 ◽  
Author(s):  
Peter G. Ryan ◽  
Ben J. Dilley ◽  
Robert A. Ronconi ◽  
Maëlle Connan
Keyword(s):  
South America ◽  
Atlantic Ocean ◽  
South Atlantic ◽  
South Atlantic Ocean ◽  
The West ◽  
International Convention ◽  
To Come ◽  
Made In China ◽  
Central South ◽  
Made In

Most plastic debris floating at sea is thought to come from land-based sources, but there is little direct evidence to support this assumption. Since 1984, stranded debris has been recorded along the west coast of Inaccessible Island, a remote, uninhabited island in the central South Atlantic Ocean that has a very high macrodebris load (∼5 kg·m−1). Plastic drink bottles show the fastest growth rate, increasing at 15% per year compared with 7% per year for other debris types. In 2018, we examined 2,580 plastic bottles and other containers (one-third of all debris items) that had accumulated on the coast, and a further 174 bottles that washed ashore during regular monitoring over the course of 72 d (equivalent to 800 bottles·km−1·y−1). The oldest container was a high-density polyethylene canister made in 1971, but most were polyethylene terephthalate drink bottles of recent manufacture. Of the bottles that washed up during our survey, 90% were date-stamped within 2 y of stranding. In the 1980s, two-thirds of bottles derived from South America, carried 3,000 km by the west wind drift. By 2009, Asia had surpassed South America as the major source of bottles, and by 2018, Asian bottles comprised 73% of accumulated and 83% of newly arrived bottles, with most made in China. The rapid growth in Asian debris, mainly from China, coupled with the recent manufacture of these items, indicates that ships are responsible for most of the bottles floating in the central South Atlantic Ocean, in contravention of International Convention for the Prevention of Pollution from Ships regulations.

A Numerical Study of the Impact of Greenhouse Gases on the South Atlantic Ocean Climatology

2004 ◽  
Vol 66 (1/2) ◽  
pp. 163-189 ◽  
Author(s):  
Ilana Wainer ◽  
Andrea Taschetto ◽  
Bette Otto-Bliesner ◽  
Esther Brady
Keyword(s):  
Atlantic Ocean ◽  
Greenhouse Gases ◽  
Numerical Study ◽  
South Atlantic ◽  
South Atlantic Ocean ◽  
The South ◽  
The Impact

scholarly journals Migration and summer destinations of humpback whales (Megaptera novaeangliae) in the western South Atlantic Ocean

2020 ◽  
pp. 113-118
Author(s):  
Alexandre N. Zerbini ◽  
Artur Andriolo ◽  
Mads Peter Heide-Jorgensen ◽  
Sergio C. Moreira ◽  
Jose Luis Pizzorno ◽  
...  
Keyword(s):  
South America ◽  
Atlantic Ocean ◽  
Satellite Telemetry ◽  
South Atlantic ◽  
South Atlantic Ocean ◽  
Humpback Whales ◽  
Telemetry Data ◽  
The South ◽  
The Antarctic ◽  
Feeding Grounds

Southern Hemisphere humpback whales (Megaptera novaeangliae) migrate from wintering grounds in tropical latitudes to feeding areas in the Antarctic Ocean. In 2003 and 2005, satellite transmitters were deployed on humpback whales on their wintering grounds off the eastern coast of South America (Breeding Stock A). Seven whales were tracked for a period of 16 to 205 days travelling between 902 and 7,258km. The tracks of these whales provided partial or full information on the migratory schedule, migration routes and location of the feeding ground in the Southern Oceans. Whales departed from the coast of Brazil from late October to late December between 20˚ and 25˚S and gradually moved away from the South American coast as they moved towards high latitudes. They followed a somewhat direct, linear path, with an approximate geographic heading of 170˚. Satellite telemetry data indicated that the migratory corridors are restricted to a relatively narrow (~500–800km) strip in the South Atlantic Ocean. Migration speed to the feeding grounds averaged 80.2km/day and lasted from 40–58 days. Four individuals arrived at the feeding ground located to the north of the South Sandwich Islands, where they were tracked up to 102 days. Movements in this area were erratic at a mean travelling speed of 22.3km/day. Satellite telemetry data indicate that the main feeding grounds for the population wintering off eastern South America lie between 22˚W and 33˚W and in the southern South Atlantic Ocean south of the Antarctic Convergence but north of 60˚S. This is only partially consistent with the currently proposed stock boundaries for this population on the feeding grounds.

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