scholarly journals The Energy Budget of the Polar Atmosphere in MERRA

2012 ◽  
Vol 25 (1) ◽  
pp. 5-24 ◽  
Author(s):  
Richard I. Cullather ◽  
Michael G. Bosilovich
Keyword(s):  
Energy Budget ◽  
The Arctic ◽  
Polar Regions ◽  
Polar Cap ◽  
The South ◽  
Atmospheric Energy ◽  
In Situ Observations ◽  
Energy Convergence ◽  
South Polar

Abstract Components of the atmospheric energy budget from the Modern-Era Retrospective Analysis for Research and Applications (MERRA) are evaluated in polar regions for the period 1979–2005 and compared with previous estimates, in situ observations, and contemporary reanalyses. Closure of the budget is reflected by the analysis increments term, which indicates an energy surplus of 11 W m−2 over the North Polar cap (70°–90°N) and 22 W m−2 over the South Polar cap (70°–90°S). Total atmospheric energy convergence from MERRA compares favorably with previous studies for northern high latitudes but exceeds the available previous estimate for the South Polar cap by 46%. Discrepancies with the Southern Hemisphere energy transport are largest in autumn and may be related to differences in topography with earlier reanalyses. For the Arctic, differences between MERRA and other sources in top of atmosphere (TOA) and surface radiative fluxes are largest in May. These differences are concurrent with the largest discrepancies between MERRA parameterized and observed surface albedo. For May, in situ observations of the upwelling shortwave flux in the Arctic are 80 W m−2 larger than MERRA, while the MERRA downwelling longwave flux is underestimated by 12 W m−2 throughout the year. Over grounded ice sheets, the annual mean net surface energy flux in MERRA is erroneously nonzero. Contemporary reanalyses from the Climate Forecast Center (CFSR) and the Interim Re-Analyses of the European Centre for Medium-Range Weather Forecasts (ERA-I) are found to have better surface parameterizations; however, these reanalyses also disagree with observed surface and TOA energy fluxes. Discrepancies among available reanalyses underscore the challenge of reproducing credible estimates of the atmospheric energy budget in polar regions.

scholarly journals Integrative and comprehensive Understanding on Polar Environments (iCUPE): the concept and initial results

2020 ◽  
Author(s):  
Tuukka Petäjä ◽  
Ella-Maria Duplissy ◽  
Ksenia Tabakova ◽  
Julia Schmale ◽  
Barbara Altstädter ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Natural Resources ◽  
Satellite Remote Sensing ◽  
Integrated Approach ◽  
The Arctic ◽  
Polar Regions ◽  
Comprehensive Understanding ◽  
In Situ Observations ◽  
Initial Results

Abstract. The role of polar regions increases in terms of megatrends such as globalization, new transport routes, demography and use of natural resources consequent effects of regional and transported pollutant concentrations. We set up the ERA-PLANET Strand 4 project iCUPE – integrative and Comprehensive Understanding on Polar Environments to provide novel insights and observational data on global grand challenges with an Arctic focus. We utilize an integrated approach combining in situ observations, satellite remote sensing Earth Observations (EO) and multi-scale modeling to synthesize data from comprehensive long-term measurements, intensive campaigns and satellites to deliver data products, metrics and indicators to the stakeholders concerning the environmental status, availability and extraction of natural resources in the polar areas. The iCUPE work consists of thematic state-of-the-art research and provision of novel data in atmospheric pollution, local sources and transboundary transport, characterization of arctic surfaces and their changes, assessment of concentrations and impacts of heavy metals and persistent organic pollutants and their cycling, quantification of emissions from natural resource extraction and validation and optimization of satellite Earth Observation (EO) data streams. In this paper we introduce the iCUPE project and summarize initial results arising out of integration of comprehensive in situ observations, satellite remote sensing and multiscale modeling in the Arctic context.

scholarly journals Wintertime enhancements of sea salt aerosol in polar regions consistent with a sea ice source from blowing snow

2017 ◽  
Vol 17 (5) ◽  
pp. 3699-3712 ◽  
Author(s):  
Jiayue Huang ◽  
Lyatt Jaeglé
Keyword(s):  
Sea Ice ◽  
Open Ocean ◽  
Sea Salt ◽  
The Arctic ◽  
Polar Regions ◽  
Blowing Snow ◽  
In Situ Observations ◽  
Frost Flowers ◽  
Mass Concentrations

Abstract. Sea salt aerosols (SSA) are generated via air bubbles bursting at the ocean surface as well as by wind mobilization of saline snow and frost flowers over sea-ice-covered areas. The relative magnitude of these sources remains poorly constrained over polar regions, affecting our ability to predict their impact on halogen chemistry, cloud formation, and climate. We implement a blowing snow and a frost flower emission scheme in the GEOS-Chem global chemical transport model, which we validate against multiyear (2001–2008) in situ observations of SSA mass concentrations at three sites in the Arctic, two sites in coastal Antarctica, and from the 2008 ICEALOT cruise in the Arctic. A simulation including only open ocean emissions underestimates SSA mass concentrations by factors of 2–10 during winter–spring for all ground-based and ship-based observations. When blowing snow emissions are added, the model is able to reproduce observed wintertime SSA concentrations, with the model bias decreasing from a range of −80 to −34 % for the open ocean simulation to −2 to +9 % for the simulation with blowing snow emissions. We find that the frost flower parameterization cannot fully explain the high wintertime concentrations and displays a seasonal cycle decreasing too rapidly in early spring. Furthermore, the high day-to-day variability of observed SSA is better reproduced by the blowing snow parameterization. Over the Arctic (> 60° N) (Antarctic, > 60° S), we calculate that submicron SSA emissions from blowing snow account for 1.0 Tg yr−1 (2.5 Tg yr−1), while frost flower emissions lead to 0.21 Tg yr−1 (0.25 Tg yr−1) compared to 0.78 Tg yr−1 (1.0 Tg yr−1) from the open ocean. Blowing snow emissions are largest in regions where persistent strong winds occur over sea ice (east of Greenland, over the central Arctic, Beaufort Sea, and the Ross and Weddell seas). In contrast, frost flower emissions are largest where cold air temperatures and open leads are co-located (over the Canadian Arctic Archipelago, coastal regions of Siberia, and off the Ross and Ronne ice shelves). Overall, in situ observations of mass concentrations of SSA suggest that blowing snow is likely to be the dominant SSA source during winter, with frost flowers playing a much smaller role.

scholarly journals Wintertime enhancements of sea salt aerosol in polar regions consistent with a sea-ice source from blowing snow

2016 ◽  
Author(s):  
Jiayue Huang ◽  
Lyatt Jaeglé
Keyword(s):  
Sea Ice ◽  
Open Ocean ◽  
Sea Salt ◽  
The Arctic ◽  
Polar Regions ◽  
Blowing Snow ◽  
In Situ Observations ◽  
Frost Flowers ◽  
Mass Concentrations

Abstract. Sea salt aerosols (SSA) are generated via air bubbles bursting at the ocean surface, as well as by wind mobilization of saline snow and frost flowers over sea-ice covered areas. The relative magnitude of these sources remains poorly constrained over polar regions, affecting our ability to predict their impact on halogen chemistry, cloud formation and climate. We implement a blowing snow and a frost flower emission scheme in the GEOS-Chem global chemical transport model, which we validate against multi-year (2001–2008) in situ observations of SSA mass concentrations at three sites in the Arctic, two sites in coastal Antarctica, as well as during a cruise in the Arctic (ICEALOT, 2008). A simulation including only open ocean emissions underestimates SSA mass concentrations by factors of 2–10 during winter-spring for all ground-based and ship-based observations. When blowing snow emissions are added, the model is able to reproduce observed wintertime SSA concentrations, with the model bias decreasing from a range of −80 % to −34 % for the open ocean simulation to −2 % to +9 % for the simulation with blowing snow emissions. We find that the frost flower parameterization cannot fully explain the high wintertime concentrations and displays a seasonal cycle decreasing too rapidly in early spring. Furthermore, the high day-to-day variability of observed SSA is better reproduced by the blowing snow parameterization. Over the Arctic (Antarctic), we calculate that submicron SSA emissions from blowing snow account for 1.0 (2.5) Tg yr−1, while frost flower emissions lead to 0.25 (0.14) Tg yr−1 compared to 0.78 (1.0) Tg yr−1 from the open ocean. Blowing snow emissions are largest in regions where persistent strong winds occur over sea ice (East of Greenland, over the central Arctic, Beaufort Sea, as well as the Ross and Weddell Seas). In contrast, frost flower emissions are largest where cold air temperatures, open leads and mild winds are co-located (over the Canadian Arctic Archipelago, coastal regions of Siberia, and off the Ross and Ronne ice shelves). Overall, in situ observations of mass concentrations of SSA suggest that blowing snow is likely to be the dominant SSA source during winter, with frost flowers playing a much smaller role.

scholarly journals International Arctic Systems for Observing the Atmosphere: An International Polar Year Legacy Consortium

2016 ◽  
Vol 97 (6) ◽  
pp. 1033-1056 ◽  
Author(s):  
Taneil Uttal ◽  
Sandra Starkweather ◽  
James R. Drummond ◽  
Timo Vihma ◽  
Alexander P. Makshtas ◽  
...  
Keyword(s):  
United States ◽  
The United States ◽  
Satellite Observations ◽  
The Arctic ◽  
International Polar Year ◽  
Network Measurements ◽  
International Polar ◽  
In Situ Observations ◽  
Arctic Atmosphere

Abstract International Arctic Systems for Observing the Atmosphere (IASOA) activities and partnerships were initiated as a part of the 2007–09 International Polar Year (IPY) and are expected to continue for many decades as a legacy program. The IASOA focus is on coordinating intensive measurements of the Arctic atmosphere collected in the United States, Canada, Russia, Norway, Finland, and Greenland to create synthesis science that leads to an understanding of why and not just how the Arctic atmosphere is evolving. The IASOA premise is that there are limitations with Arctic modeling and satellite observations that can only be addressed with boots-on-the-ground, in situ observations and that the potential of combining individual station and network measurements into an integrated observing system is tremendous. The IASOA vision is that by further integrating with other network observing programs focusing on hydrology, glaciology, oceanography, terrestrial, and biological systems it will be possible to understand the mechanisms of the entire Arctic system, perhaps well enough for humans to mitigate undesirable variations and adapt to inevitable change.

scholarly journals An algorithm for detecting <i>Trichodesmium</i> surface blooms in the South Western Tropical Pacific

2011 ◽  
Vol 8 (3) ◽  
pp. 5653-5689 ◽  
Author(s):  
C. Dupouy ◽  
D. Benielli-Gary ◽  
J. Neveux ◽  
Y. Dandonneau ◽  
T. K. Westberry
Keyword(s):  
Total Surface Area ◽  
Tropical Pacific ◽  
The South ◽  
Western Tropical Pacific ◽  
Tropical Oceans ◽  
Novel Approach ◽  
Monthly Distribution ◽  
C And N ◽  
In Situ Observations

Abstract. Trichodesmium, a major colonial cyanobacterial nitrogen fixer, forms large blooms in NO3-depleted tropical oceans and enhances CO2 sequestration by the ocean due to its ability to fix dissolved dinitrogen. Thus, its importance in C and N cycles requires better estimates of its distribution at basin to global scales. However, existing algorithms to detect them from satellite have not yet been successful in the South Western Tropical Pacific (SWTP). Here, a novel approach based on radiance anomaly spectra (RAS) observed in SeaWiFS imagery is used to detect Trichodesmium during the austral summertime in the SWTP. Selected pixels are characterized by a restricted range of parameters quantifying RAS spectra quantitative parameters (e.g. slope, intercept, curvature). The fraction of valid pixels identified as Trichodesmium surface blooms in the region 5° S–25° S 160° E–190° E is low (between 0.01 and 0.2 %), but is about 100 times higher than suggested by previous algorithms. This represents a total surface area which varies from 1500 to 20 000 km2. A monthly distribution of Trichodesmium surface accumulations in the SWTP is presented which demonstrates that the number of selected pixels peaks in November–February each year, consistent with field observations. This approach was validated with in situ observations of Trichodesmium surface accumulations for the period 1998–2010.

scholarly journals Exploration of the South Polar Regions

Nature ◽  
1872 ◽  
Vol 7 (165) ◽  
pp. 138-140
Keyword(s):  
Polar Regions ◽  
The South ◽  
South Polar

Radar detection of subglacial water under the south polar cap of Mars: Where are we now?

2020 ◽  
Author(s):  
R. Orosei ◽  
G. Caprarelli ◽  
M. Cartacci ◽  
A. Cicchetti ◽  
B. Cosciotti ◽  
...  
Keyword(s):  
Radar Detection ◽  
Polar Cap ◽  
The South ◽  
South Polar
Sign in / Sign up

Export Citation Format

Share Document