scholarly journals A Comparison of Atmospheric Reanalysis Products for the Arctic Ocean and Implications for Uncertainties in Air–Sea Fluxes

2014 ◽  
Vol 27 (14) ◽  
pp. 5411-5421 ◽  
Author(s):  
Ayan H. Chaudhuri ◽  
Rui M. Ponte ◽  
An T. Nguyen
Keyword(s):  
Arctic Ocean ◽  
Air Temperature ◽  
Surface Air Temperature ◽  
Specific Humidity ◽  
Shortwave Radiation ◽  
The Arctic ◽  
The Arctic Ocean ◽  
Temperature And Humidity ◽  
Meridional Winds ◽  
Similar Solutions

Abstract The uncertainties related to atmospheric fields in the Arctic Ocean from commonly used and recently available reanalysis products are investigated. Fields from the 1) ECMWF Interim Re-Analysis (ERA-Interim), 2) Common Ocean–Ice Reference Experiment version 2 (CORE2), 3) Japanese 25-yr Reanalysis Project (JRA-25), 4) NCEP–NCAR reanalysis, 5) NCEP Climate Forecast System Reanalysis (CFSR), and 6) Modern-Era Retrospective Analysis for Research and Applications (MERRA) are evaluated against satellite-derived and in situ observations for zonal and meridional winds, precipitation, specific humidity, surface air temperature, and downwelling longwave and shortwave radiation fluxes. Comparison to reference observations shows that for variables such as air temperature and humidity, all reanalysis products have similar solutions. However, other variables such as winds, precipitation, and radiation show large spreads. The magnitude of uncertainties in all fields is large when compared to the signal. Biases in Arctic cloud parameterizations and predicted temperature and humidity profiles in reanalyses as discussed in other studies are likely common sources of error that affect surface downwelling radiation, air temperature, humidity, and precipitation.

scholarly journals An energy budget approach to understand the Arctic warming during the Last Interglacial

2021 ◽  
Author(s):  
Marie Sicard ◽  
Masa Kageyama ◽  
Sylvie Charbit ◽  
Pascale Braconnot ◽  
Jean-Baptiste Madeleine
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Air Temperature ◽  
Energy Budget ◽  
Surface Air Temperature ◽  
The Arctic ◽  
Last Interglacial ◽  
Near Surface ◽  
Arctic Warming ◽  
The Arctic Ocean

Abstract. The Last Interglacial period (129–116 ka BP) is characterized by a strong orbital forcing which leads to a different seasonal and latitudinal distribution of insolation compared to the pre-industrial period. In particular, these changes amplify the seasonality of the insolation in the high latitudes of the northern hemisphere. Here, we investigate the Arctic climate response to this forcing by comparing the CMIP6 lig127k and pi-Control simulations performed with the IPSL-CM6A-LR model. Using an energy budget framework, we analyse the interactions between the atmosphere, ocean, sea ice and continents. In summer, the insolation anomaly reaches its maximum and causes a near-surface air temperature rise of 3.2 °C over the Arctic region. This warming is primarily due to a strong positive surface downwelling shortwave radiation anomaly over continental surfaces, followed by large heat transfers from the continents back to the atmosphere. The surface layers of the Arctic Ocean also receives more energy, but in smaller quantity than the continents due to a cloud negative feedback. Furthermore, while heat exchanges from the continental surfaces towards the atmosphere are strengthened, the ocean absorbs and stores the heat excess due to a decline in sea ice cover. However, the maximum near-surface air temperature anomaly does not peak in summer like insolation, but occurs in autumn with a temperature increase of 4.0 °C relative to the pre-industrial period. This strong warming is driven by a positive anomaly of longwave radiations over the Arctic ocean enhanced by a positive cloud feedback. It is also favoured by the summer and autumn Arctic sea ice retreat (−1.9 × 106 and −3.4 × 106 km2 respectively), which exposes the warm oceanic surface and allows heat stored by the ocean in summer and water vapour to be released. This study highlights the crucial role of the sea ice cover variations, the Arctic ocean, as well as changes in polar clouds optical properties on the Last Interglacial Arctic warming.

scholarly journals A Comparison of Atmospheric Reanalysis Surface Products over the Ocean and Implications for Uncertainties in Air–Sea Boundary Forcing

2013 ◽  
Vol 26 (1) ◽  
pp. 153-170 ◽  
Author(s):  
Ayan H. Chaudhuri ◽  
Rui M. Ponte ◽  
Gael Forget ◽  
Patrick Heimbach
Keyword(s):  
Air Temperature ◽  
Surface Air Temperature ◽  
Small Time ◽  
Time Variable ◽  
Specific Humidity ◽  
Shortwave Radiation ◽  
Single Product ◽  
Common Reference ◽  
Meridional Winds ◽  
Variable Errors

Abstract This paper investigates the uncertainties related to atmospheric fields from reanalysis products used in forcing ocean models. Four reanalysis products, namely from 1) the interim ECMWF Re-Analysis (ERA-Interim), 2) version 2 of the Common Reference Ocean–Ice Experiments (CORE2), 3) the 25-Year Japanese Reanalysis Project (JRA-25), and 4) NCEP–NCAR, are evaluated against satellite-derived observations for eight different fields (zonal and meridional winds, precipitation, specific humidity, continental discharge, surface air temperature, and downwelling longwave and shortwave radiation fluxes). No single product is found to agree better in all fields with satellite-derived observations. Reanalysis products are mostly comparable to each other because of their similar physical assumptions and assimilation of common observations. Adjusted atmospheric fields from the Estimating the Circulation and Climate of the Ocean (ECCO) optimizations are also in agreement with other reanalysis products. Time-mean and time-variable errors are estimated separately and mapped globally in space, based on 14-day average fields to focus on monthly to interannual periods. Time-variable errors are larger in comparison to the signal than time-mean errors for most fields, thus justifying the need to separate them for studying uncertainties as well as formulating optimization procedures. Precipitation and wind stress fields show significant time-mean and time-variable errors whereas downwelling radiation, air temperature, and humidity fields show small time-mean errors but large time-variable errors, particularly in the tropics. Uncertainties based on evaluating multiple products presented here are considerably larger than uncertainties based on single product pairs.

scholarly journals Dark Warming

2016 ◽  
Vol 29 (2) ◽  
pp. 705-719 ◽  
Author(s):  
Melissa A. Burt ◽  
David A. Randall ◽  
Mark D. Branson
Keyword(s):  
Arctic Ocean ◽  
Air Temperature ◽  
Surface Wind ◽  
Surface Air Temperature ◽  
Longwave Radiation ◽  
Surface Wind Speed ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
The Arctic Ocean ◽  
Autumn And Winter

Abstract As the Arctic sea ice thins and ultimately disappears in a warming climate, its insulating power decreases. This causes the surface air temperature to approach the temperature of the relatively warm ocean water below the ice. The resulting increases in air temperature, water vapor, and cloudiness lead to an increase in the surface downwelling longwave radiation (DLR), which enables a further thinning of the ice. This positive ice–insulation feedback operates mainly in the autumn and winter. A climate change simulation with the Community Earth System Model shows that, averaged over the year, the increase in Arctic DLR is 3 times stronger than the increase in Arctic absorbed solar radiation at the surface. The warming of the surface air over the Arctic Ocean during fall and winter creates a strong thermal contrast with the colder surrounding continents. Sea level pressure falls over the Arctic Ocean, and the high-latitude circulation reorganizes into a shallow “winter monsoon.” The resulting increase in surface wind speed promotes stronger surface evaporation and higher humidity over portions of the Arctic Ocean, thus reinforcing the ice–insulation feedback.

Is summer sea surface temperature over the Arctic Ocean connected to winter air temperature over North America?

2016 ◽  
Vol 70 (1) ◽  
pp. 19-27
Author(s):  
M Ogi ◽  
S Rysgaard ◽  
DG Barber ◽  
T Nakamura ◽  
B Taguchi
Keyword(s):  
North America ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Arctic Ocean ◽  
Air Temperature ◽  
Sea Surface ◽  
The Arctic ◽  
The Arctic Ocean ◽  
Winter Air Temperature

scholarly journals An Evaluation of Surface Atmospheric Changes over the Arctic Ocean for 2000–09 Using Recent Reanalyses

2015 ◽  
Vol 19 (2) ◽  
pp. 1-18 ◽  
Author(s):  
Ayan H. Chaudhuri ◽  
Rui M. Ponte
Keyword(s):  
Arctic Ocean ◽  
Extreme Event ◽  
Longwave Radiation ◽  
Remotely Sensed ◽  
Surface Radiation ◽  
Shortwave Radiation ◽  
The Arctic ◽  
Near Surface ◽  
The Arctic Ocean ◽  
Ice Retreat

Abstract The authors examine five recent reanalysis products [NCEP Climate Forecast System Reanalysis (CFSR), Modern-Era Retrospective Analysis for Research and Applications (MERRA), Japanese 25-year Reanalysis Project (JRA-25), Interim ECMWF Re-Analysis (ERA-Interim), and Arctic System Reanalysis (ASR)] for 1) trends in near-surface radiation fluxes, air temperature, and humidity, which are important indicators of changes within the Arctic Ocean and also influence sea ice and ocean conditions, and 2) fidelity of these atmospheric fields and effects for an extreme event: namely, the 2007 ice retreat. An analysis of trends over the Arctic for the past decade (2000–09) shows that reanalysis solutions have large spreads, particularly for downwelling shortwave radiation. In many cases, the differences in significant trends between the five reanalysis products are comparable to the estimated trend within a particular product. These discrepancies make it difficult to establish a consensus on likely changes occurring in the Arctic solely based on results from reanalyses fields. Regarding the 2007 ice retreat event, comparisons with remotely sensed estimates of downwelling radiation observations against these reanalysis products present an ambiguity. Remotely sensed observations from a study cited herewith suggest a large increase in downwelling summertime shortwave radiation and decrease in downwelling summertime longwave radiation from 2006 and 2007. On the contrary, the reanalysis products show only small gains in summertime shortwave radiation, if any; however, all the products show increases in downwelling longwave radiation. Thus, agreement within reanalysis fields needs to be further checked against observations to assess possible biases common to all products.

Assessment of Temperature and Specific Humidity Inversions and Their Relationships in Three Global Reanalysis Products over the Arctic Ocean

2021 ◽  
Vol 60 (4) ◽  
pp. 493-511
Author(s):  
Liang Chang ◽  
Shiqiang Wen ◽  
Guoping Gao ◽  
Zhen Han ◽  
Guiping Feng ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Specific Humidity ◽  
The Arctic ◽  
Weather Forecasts ◽  
The Arctic Ocean ◽  
Temperature Inversions ◽  
Global Reanalysis ◽  
Less Common Multiple ◽  
Better Than

AbstractCharacteristics of temperature inversions (TIs) and specific humidity inversions (SHIs) and their relationships in three of the latest global reanalyses—the European Centre for Medium-Range Weather Forecasts Interim Reanalysis (ERA-I), the Japanese 55-year Reanalysis (JRA-55), and the ERA5—are assessed against in situ radiosonde (RS) measurements from two expeditions over the Arctic Ocean. All reanalyses tend to detect many fewer TI and SHI occurrences, together with much less common multiple TIs and SHIs per profile than are seen in the RS data in summer 2008, winter 2015, and spring 2015. The reanalyses generally depict well the relationships among TI characteristics seen in RS data, except for the TIs below 400 m in summer, as well as above 1000 m in summer and winter. The depth is simulated worst by the reanalyses among the SHI characteristics, which may result from its sensitivity to the uncertainties in specific humidity in the reanalyses. The strongest TI per profile in RS data exhibits more robust dependency on surface conditions than the strongest SHI per profile, and the former is better presented by the reanalyses than the latter. Furthermore, all reanalyses have difficulties simulating the relationships between TIs and SHIs, together with the correlations between the simultaneous inversions. The accuracy and vertical resolution in the reanalyses are both important to properly capture occurrence and characteristics of the Arctic inversions. In general, ERA5 performs better than ERA-I and JRA-55 in depicting the relationships among the TIs. However, the representation of SHIs is more challenging than TIs in all reanalyses over the Arctic Ocean.

scholarly journals Climate change and the Arctic hydrologic cycle as calculated by a global coupled atmosphere–ocean model

1995 ◽  
Vol 21 ◽  
pp. 91-95 ◽  
Author(s):  
James R. Miller ◽  
Gary L. Russell
Keyword(s):  
Arctic Ocean ◽  
River Discharge ◽  
Surface Air Temperature ◽  
Horizontal Resolution ◽  
Ocean Model ◽  
Hydrologic Cycle ◽  
Transient Simulation ◽  
The Arctic ◽  
Glacial Ice ◽  
The Arctic Ocean

A global coupled atmosphere–ocean model is used to examine the hydrologic cycle of the Arctic Ocean. The model has a horizontal resolution of 4° × 5°, nine vertical layers in the atmosphere and 13 in the ocean. River discharge into the Arctic Ocean is included by allowing runoff from each continental grid box to flow downstream according to a specified direction file and a speed that depends on topography. A 74 year control simulation of the present climate is used to examine variability of the hydrologic cycle, including precipitation, sea ice, glacial ice and river discharge. A 74 year transient simulation in which atmospheric CO2increases each year at a compound rate оf 1% is then used to examine potential changes in the hydrologic cycle. Among these changes are a 4°C increase in mean annual surface air temperature in the Arctic Ocean, a decrease in ice cover which begins after 35 years, and increases in river discharge and cloud cover. There is little change in the net difference between precipitation and evaporation. Also in the transient simulation, glacial ice on Greenland decreases relative to the control.

scholarly journals Impact of Poleward Moisture Transport from the North Pacific on the Acceleration of Sea Ice Loss in the Arctic since 2002

2017 ◽  
Vol 30 (17) ◽  
pp. 6757-6769 ◽  
Author(s):  
H. J. Lee ◽  
M. O. Kwon ◽  
S.-W. Yeh ◽  
Y.-O. Kwon ◽  
W. Park ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
North Pacific ◽  
Moisture Transport ◽  
Arctic Sea Ice ◽  
Specific Humidity ◽  
The Arctic ◽  
The North ◽  
The Arctic Ocean ◽  
The North Pacific

Abstract Arctic sea ice area (SIA) during late summer and early fall decreased substantially over the last four decades, and its decline accelerated beginning in the early 2000s. Statistical analyses of observations show that enhanced poleward moisture transport from the North Pacific to the Arctic Ocean contributed to the accelerated SIA decrease during the most recent period. As a consequence, specific humidity in the Arctic Pacific sector significantly increased along with an increase of downward longwave radiation beginning in 2002, which led to a significant acceleration in the decline of SIA in the Arctic Pacific sector. The resulting sea ice loss led to increased evaporation in the Arctic Ocean, resulting in a further increase of the specific humidity in mid-to-late fall, thus acting as a positive feedback to the sea ice loss. The overall set of processes is also found in a long control simulation of a coupled climate model.

scholarly journals Seasonal Variation of Surface Temperature Change during the Last Several Decades

2011 ◽  
Vol 24 (15) ◽  
pp. 3817-3821 ◽  
Author(s):  
Syukuro Manabe ◽  
Jeffrey Ploshay ◽  
Ngar-Cheung Lau
Keyword(s):  
Seasonal Variation ◽  
Surface Temperature ◽  
Arctic Ocean ◽  
Temperature Change ◽  
Surface Air Temperature ◽  
Recent Change ◽  
The Arctic ◽  
Climatic Research Unit ◽  
Surface Temperature Change ◽  
The Arctic Ocean

Abstract Using the historical surface temperature dataset compiled by Climatic Research Unit of the University of East Anglia and the Hadley Centre of the United Kingdom, this study examines the seasonal and latitudinal profile of the surface temperature change observed during the last several decades. It reveals that the recent change in zonal-mean surface air temperature is positive at practically all latitudes. In the Northern Hemisphere, the warming increases with increasing latitude and is large in the Arctic Ocean during much of the year except in summer, when it is small. At the Antarctic coast and in the northern part of the circumpolar ocean (near 55°S), where limited data are available, the changes appear to be small during most seasons, though the warming is notable at the coast in winter. However, this warming is much less than the warming over the Arctic Ocean. The seasonal variation of the surface temperature change appears to be broadly consistent with the result from a global warming experiment that was conducted some time ago using a coupled atmosphere–ocean–land model.

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