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

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.

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Characteristics of low-level temperature inversions over the Arctic Ocean during the CHINARE 2018 campaign in summer

Atmospheric Environment ◽

10.1016/j.atmosenv.2021.118537 ◽

2021 ◽

pp. 118537

Author(s):

Lei Zhang ◽

Jian Li ◽

Minghu Ding ◽

Jianping Guo ◽

Lingen Bian ◽

...

Keyword(s):

Arctic Ocean ◽

The Arctic ◽

Low Level ◽

The Arctic Ocean ◽

Temperature Inversions

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Using ship-borne observations of methane isotopic ratio in the Arctic Ocean to understand methane sources in the Arctic

10.5194/acp-2019-595 ◽

2019 ◽

Author(s):

Antoine Berchet ◽

Isabelle Pison ◽

Patrick M. Crill ◽

Brett Thornton ◽

Philippe Bousquet ◽

...

Keyword(s):

Arctic Ocean ◽

Large Scale ◽

Transport Model ◽

Isotopic Ratio ◽

The Arctic ◽

Isotopic Ratios ◽

Air Masses ◽

Remote Areas ◽

The Arctic Ocean

Abstract. Due to the large variety and heterogeneity of sources in remote areas hard to document, the Arctic regional methane budget remain very uncertain. In situ campaigns provide valuable data sets to reduce these uncertainties. Here we analyse data from the SWERUS-C3 campaign, on-board the icebreaker Oden, that took place during summer 2014 in the Arctic Ocean along the Northern Siberian and Alaskan shores. Total concentrations of methane, as well as isotopic ratios were measured continuously during this campaign for 35 days in July and August 2014. Using a chemistry-transport model, we link observed concentrations and isotopic ratios to regional emissions and hemispheric transport structures. A simple inversion system helped constraining source signatures from wetlands in Siberia and Alaska and oceanic sources, as well as the isotopic composition of lower stratosphere air masses. The variation in the signature of low stratosphere air masses, due to strongly fractionating chemical reactions in the stratosphere, was suggested to explain a large share of the observed variability in isotopic ratios. These points at required efforts to better simulate large scale transport and chemistry patterns to use isotopic data in remote areas. It is found that constant and homogeneous source signatures for each type of emission in the region (mostly wetlands and oil and gas industry) is not compatible with the strong synoptic isotopic signal observed in the Arctic. A regional gradient in source signatures is highlighted between Siberian and Alaskan wetlands, the later ones having a lighter signatures than the first ones. Arctic continental shelf sources are suggested to be a mixture of methane from a dominant thermogenic origin and a secondary biogenic one, consistent with previous in-situ isotopic analysis of seepage along the Siberian shores.

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INTAROS synthesis of gap analysis of the existing Arctic observing systems

10.5194/egusphere-egu2020-20091 ◽

2020 ◽

Author(s):

Roberta Pirazzini ◽

Michael Tjernström ◽

Stein Sandven ◽

Hanne Sagen ◽

Torill Hamre ◽

...

Keyword(s):

Arctic Ocean ◽

Gap Analysis ◽

Satellite Observations ◽

The Arctic ◽

Reference Level ◽

Data Handling ◽

Network Concept ◽

The Arctic Ocean ◽

Observing Systems

A comprehensive assessment of a substantial subset of Arctic observing systems, data collections and satellite products across scientific disciplines was carried out in INTAROS, also including data repositories and a brief scientific gap analysis. The assessments cover a multitude of aspects such as sustainability, technical maturity and data handling for the entire chain from observation to users, including metadata procedures and availability to data. Community based environment monitoring programs were surveyed and assessed separately; they do not form part of the present assessment.The assessed observing systems were first ranked according to general sustainability and other aspects, were analyzed subsequently. While the range of sustainability is large, it was found that high scores on all other aspects, such as for data handling and technical maturity, are more likely for systems with high sustainability. Moreover, many systems with high sustainability, as well as advanced systems for data handling and availability in place, resulted from national commitments to international monitoring or infrastructure programs, several of which are not necessarily particular to the Arctic.Traditionally, terrestrial and atmospheric observation network assessments build on the network concept with a &#8220;comprehensive&#8221; level including all observations, a &#8220;baseline&#8221; level of an agreed subset of sustained observations, and a &#8220;reference&#8221; level, with observations adhering to specific calibrations and traceability criteria. Examples from atmospheric observations are the &#8220;comprehensive&#8221; global GCOS radiosounding network, the &#8220;baseline&#8221; GUAN (GCOS Upper Air Network) and &#8220;reference&#8221; GRUAN (GCOS Reference Upper Air Network) networks. With the lack of in-situ observations especially from the Arctic Ocean and the logistical difficulties to deploy new stations, it was concluded that this concept does not work well in the Arctic.In summary, we recommend that:<ul><li>advancement in Arctic observing should be done in international global or regional programs with well-established routines and procedures, rather than to invest in new Arctic-specific programs</li> <li>investments in new instruments and techniques be done at already established sites, to benefit interdisciplinary studies and optimize infrastructure costs</li> <li>more observations be based on ships of opportunity and that a subset of ocean, sea-ice and atmosphere observations always be made on all research expeditions, regardless of their scientific aim</li> <li>the funding structures for science expeditions is reviewed to maintain, and preferably increase, the number of expeditions and to safeguard funding for appropriate data handling and storage</li> <li>observing-network concept for the atmosphere over the Arctic Ocean is revised, so that coupled reanalyses represent the &#8220;comprehensive level&#8221;, satellite observations complemented with available in-situ data is the &#8220;baseline level&#8221;, while scientific expeditions is the &#8220;reference level&#8221;. This requires substantial improvements in reanalysis, better numerical models and data assimilation, better satellite observations and improved data handling and accessibility for scientific expeditions.</li> </ul>

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Gelatinous zooplankton of the Arctic Ocean: in situ observations under the ice

Polar Biology ◽

10.1007/s00300-004-0677-2 ◽

2004 ◽

Vol 28 (3) ◽

pp. 207-217 ◽

Cited By ~ 48

Author(s):

K. A. Raskoff ◽

J. E. Purcell ◽

R. R. Hopcroft

Keyword(s):

Arctic Ocean ◽

Gelatinous Zooplankton ◽

The Arctic ◽

The Arctic Ocean ◽

In Situ Observations

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Synthesis of integrated primary production in the Arctic Ocean: II. In situ and remotely sensed estimates

Progress In Oceanography ◽

10.1016/j.pocean.2012.11.005 ◽

2013 ◽

Vol 110 ◽

pp. 107-125 ◽

Cited By ~ 102

Author(s):

Victoria J. Hill ◽

Patricia A. Matrai ◽

Elise Olson ◽

S. Suttles ◽

Mike Steele ◽

...

Keyword(s):

Primary Production ◽

Arctic Ocean ◽

Remotely Sensed ◽

The Arctic ◽

The Arctic Ocean

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Intercomparison of Salinity Products in the Beaufort Gyre and Arctic Ocean

Remote Sensing ◽

10.3390/rs14010071 ◽

2021 ◽

Vol 14 (1) ◽

pp. 71

Author(s):

Sarah B. Hall ◽

Bulusu Subrahmanyam ◽

James H. Morison

Keyword(s):

Soil Moisture ◽

Arctic Ocean ◽

Satellite Observations ◽

Sea Surface ◽

Sea Surface Salinity ◽

The Arctic ◽

Surface Salinity ◽

Beaufort Gyre ◽

The Arctic Ocean

Salinity is the primary determinant of the Arctic Ocean’s density structure. Freshwater accumulation and distribution in the Arctic Ocean have varied significantly in recent decades and certainly in the Beaufort Gyre (BG). In this study, we analyze salinity variations in the BG region between 2012 and 2017. We use in situ salinity observations from the Seasonal Ice Zone Reconnaissance Surveys (SIZRS), CTD casts from the Beaufort Gyre Exploration Project (BGP), and the EN4 data to validate and compare with satellite observations from Soil Moisture Active Passive (SMAP), Soil Moisture and Ocean Salinity (SMOS), and Aquarius Optimally Interpolated Sea Surface Salinity (OISSS), and Arctic Ocean models: ECCO, MIZMAS, HYCOM, ORAS5, and GLORYS12. Overall, satellite observations are restricted to ice-free regions in the BG area, and models tend to overestimate sea surface salinity (SSS). Freshwater Content (FWC), an important component of the BG, is computed for EN4 and most models. ORAS5 provides the strongest positive SSS correlation coefficient (0.612) and lowest bias to in situ observations compared to the other products. ORAS5 subsurface salinity and FWC compare well with the EN4 data. Discrepancies between models and SIZRS data are highest in GLORYS12 and ECCO. These comparisons identify dissimilarities between salinity products and extend challenges to observations applicable to other areas of the Arctic Ocean.

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The shallowing surface temperature inversions in the Arctic

Journal of Climate ◽

10.1175/jcli-d-20-0621.1 ◽

2021 ◽

pp. 1-30

Author(s):

Lin Zhang ◽

Minghu Ding ◽

Tingfeng Dou ◽

Yi Huang ◽

Junmei Lv ◽

...

Keyword(s):

Sea Ice ◽

Arctic Ocean ◽

21St Century ◽

Barents Sea ◽

Atmospheric Stability ◽

Heat Fluxes ◽

Spatiotemporal Variability ◽

The Arctic ◽

The Arctic Ocean ◽

Temperature Inversions

AbstractTemperature inversion plays an important role in various physical processes by affecting the atmospheric stability, regulating the development of clouds and fog, and controlling the transport of heat and moisture fluxes. In the past few decades, previous studies have analyzed the spatiotemporal variability of Arctic inversions, but few studies have investigated changes in temperature inversions. In this study, the changes in the depth of Arctic inversions in the mid-21st century are projected based on a 30-member ensemble from the Community Earth System Model Large Ensemble (CESM-LE) project. The ERA-Interim, JRA-55, and NCEP-NCAR reanalyses were employed to verify the model results. The CESM-LE can adequately reproduce the spatial distribution and trends of present-day inversion depth in the Arctic, and the simulation is better in winter. The mean inversion depth in the CESM-LE is slightly underestimated, and the discrepancy is less than 11 hPa within a reasonable range. The model results show that during the mid-21st century, the inversion depth will strongly decrease in autumn and slightly decrease in winter. The shallowing of inversion is most obvious over the Arctic Ocean, and the maximum decrease is over 65 hPa in the Pacific sector in autumn. In contrast, the largest decrease in the inversion depth, which is more than 45 hPa, occurs over the Barents Sea in winter. Moreover, the area where the inversion shallows is consistent with the area where the sea ice is retreating, indicating that the inversion depth over the Arctic Ocean in autumn and winter is likely regulated by the sea ice extent through modulating surface heat fluxes.

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Using CloudSat snowfall rate observations to constrain and characterize the uncertainties of Arctic snow-on-sea-ice

10.5194/egusphere-egu2020-11436 ◽

2020 ◽

Author(s):

Alex Cabaj ◽

Paul Kushner ◽

Alek Petty ◽

Stephen Howell ◽

Christopher Fletcher

Keyword(s):

Sea Ice ◽

Arctic Ocean ◽

Snow Depth ◽

Arctic Sea Ice ◽

The Arctic ◽

Ice Thickness ◽

Sea Ice Thickness ◽

The Arctic Ocean ◽

Ice Model

Snow on Arctic sea ice plays multiple&#8212;and sometimes contrasting&#8212;roles in several feedbacks between sea ice and the global climate system. For example, the presence of snow on sea ice may mitigate sea ice melt by increasing the sea ice albedo and enhancing the ice-albedo feedback. Conversely, snow can inhibit sea ice growth by insulating the ice from the atmosphere during the sea ice growth season. In addition to its contribution to sea ice feedbacks, snow on sea ice also poses a challenge for sea ice observations. In particular, snow contributes to uncertainties in retrievals of sea ice thickness from satellite altimetry measurements, such as those from ICESat-2. Snow-on-sea-ice models can produce basin-wide snow depth estimates, but these models require snowfall input from reanalysis products. In-situ snowfall measurements are absent over most of the Arctic Ocean, so it can be difficult to determine which reanalysis snowfall product is best suited to be used as input for a snow-on-sea-ice model.In the absence of in-situ snowfall rate measurements, measurements from satellite instruments can be used to quantify snowfall over the Arctic Ocean. The CloudSat satellite, which is equipped with a 94 GHz Cloud Profiling Radar instrument, measures vertical radar reflectivity profiles from which snowfall rates can be retrieved. This instrument provides the most extensive high-latitude snowfall rate observation dataset currently available. CloudSat&#8217;s near-polar orbit enables it to make measurements at latitudes up to 82&#176;N, with a 16-day repeat cycle, over the time period from 2006-2016.We present a calibration of reanalysis snowfall to CloudSat observations over the Arctic Ocean, which we then apply to reanalysis snowfall input for the NASA Eulerian Snow On Sea Ice Model (NESOSIM). This calibration reduces the spread in snow depths produced by NESOSIM when different reanalysis inputs are used. In light of this calibration, we revise the NESOSIM parametrizations of wind-driven snow processes, and we characterize the uncertainties in NESOSIM-generated snow depths resulting from uncertainties in snowfall input. We then extend this analysis further to estimate the resulting uncertainties in sea ice thickness retrieved from ICESat-2 when snow depth estimates from NESOSIM are used as input for the retrieval.

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Carbon dynamics in the western Arctic Ocean: insights from full-depth carbon isotope profiles of DIC, DOC, and POC

Biogeosciences ◽

10.5194/bg-9-1217-2012 ◽

2012 ◽

Vol 9 (3) ◽

pp. 1217-1224 ◽

Cited By ~ 54

Author(s):

D. R. Griffith ◽

A. P. McNichol ◽

L. Xu ◽

F. A. McLaughlin ◽

R. W. Macdonald ◽

...

Keyword(s):

Organic Carbon ◽

Arctic Ocean ◽

Carbon Isotope ◽

Dissolved Inorganic Carbon ◽

Isotope Composition ◽

Canada Basin ◽

The Arctic ◽

Arctic Ecosystems ◽

The Arctic Ocean

Abstract. Arctic warming is projected to continue throughout the coming century. Yet, our currently limited understanding of the Arctic Ocean carbon cycle hinders our ability to predict how changing conditions will affect local Arctic ecosystems, regional carbon budgets, and global climate. We present here the first set of concurrent, full-depth, dual-isotope profiles for dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), and suspended particulate organic carbon (POCsusp) at two sites in the Canada Basin of the Arctic Ocean. The carbon isotope composition of sinking and suspended POC in the Arctic contrasts strongly with open ocean Atlantic and Pacific sites, pointing to a combination of inputs to Arctic POCsusp at depth, including surface-derived organic carbon (OC), sorbed/advected OC, and OC derived from in situ DIC fixation. The latter process appears to be particularly important at intermediate depths, where mass balance calculations suggest that OC derived from in situ DIC fixation contributes up to 22% of POCsusp. As in other oceans, surface-derived OC is still a dominant source to Arctic POCsusp. Yet, we suggest that significantly smaller vertical POC fluxes in the Canada Basin make it possible to see evidence of DIC fixation in the POCsusp pool even at the bulk isotope level.

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