Atmospheric boundary layer structure over the Arctic Ocean during MOSAiC

Chen, Taigui; Yang, Qinghua; Shupe, Matthew D.; Xi, Xingya; Han, Bo; Chen, Dake; Liu, Changwei

doi:10.5194/egusphere-2023-347

Cited by 2 publications

(2 citation statements)

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“…Before calculating the MABLH, we first perform a linear interpolation to all vertical profiles to fill missing values. Then, we smooth air temperature, winds and surface water vapor mixing ratio using a 5 point running average (equivalent to 50 m in height) like in Hande et al (2012) or Peng et al (2023).…”

Section: Mablh Computation From Rssmentioning

confidence: 99%

On the Mechanisms Driving Latent Heat Flux Variations in the Northwest Tropical Atlantic

Fernández,

Speich,

Bellenger

et al. 2023

Preprint

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The Northwest Tropical Atlantic (NWTA) is a region with complex surface ocean circulation. The most prominent feature is the North Brazil Current (NBC) and its retroflection at 8ºN that leads to the formation of numerous mesoscale eddies known as NBC rings. The NWTA also receives the outflow of the Amazon River, generating freshwater plumes that can extend up to 100,000 km. These two processes affect the spatial variability of the region’s surface latent heat flux (LHF). First, the presence of surface freshwater modifies the vertical stratification of the ocean limiting the amount of heat that can be released to the atmosphere. Second, they create a highly heterogeneous mesoscale sea-surface temperature (SST) field that directly influences near-surface atmospheric circulation. These effects are illustrated byd from the ElUcidating the RolE of Cloud-Circulation Coupling in ClimAte - Ocean Atmosphere (EURECA-OA) and Atlantic Tradewind Ocean-Atmosphere Interaction Campaign (ATOMIC) experiments, satellite and reanalysis data. We decompose the LHF budget into several terms controlled by different atmospheric and oceanic processes to identify the mechanisms leading to LHF changes. We find LHF variations of up to 160 W m, of which 100 W m are associated with wind speed changes and 40 W m with SST variations. Surface currents or stratification-change associated heat release remain as second-order contributions with LHF variations of less than 10 W m each. Although this study is limited by the paucity of collocated observations, it highlights the importance of considering these three components to properly characterize LHF variability at different spatial scales.

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Section: Mablh Computation From Rssmentioning

confidence: 99%

On the Mechanisms Driving Latent Heat Flux Variations in the Northwest Tropical Atlantic

Fernández,

Speich,

Bellenger

et al. 2023

Preprint

View full text Add to dashboard Cite

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“…An overview of common identification methods can be found in Dai et al (2014) and Jozef et al (2022). One approach to define the SML height applies the bulk Richardson number Ri b (Andreas et al, 2000;Dai et al, 2014;Zhang et al, 2014;Zilitinkevich and Baklanov, 2002;Jozef et al, 2022;Peng et al, 2023). The bulk Richardson number allows the derivation of the equilibrium height where turbulence decays and from that to estimate the SML height based on a critical value (Zilitinkevich and Baklanov, 2002;Andreas et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Determining the surface mixing layer height of the Arctic atmospheric boundary layer during polar night in cloudless and cloudy conditions

Akansu

Dahlke

Siebert

et al. 2023

Preprint

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Abstract. This study analyzes turbulent properties in, and the thermodynamic structure of the Arctic atmospheric boundary layer (ABL) during winter and the transition to spring. These processes influence the evolution and longevity of clouds, and impact the surface radiative energy budget in the Arctic. For the measurements we have used an instrumental payload carried by a helium filled tethered balloon. This system was deployed between December 2019 and May 2020 during the yearlong Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition. Vertically highly resolved in situ measurements of profiles of turbulent parameters were obtained reaching from the sea ice up to several hundred meters height. The two typical states of the Arctic ABL were identified: cloudless situations with a shallow and stable ABL, and cloudy conditions maintaining a mixed ABL. We have used profile data to estimate the height of the surface mixing layer. For this purpose, a bulk Richardson number criterion approach was introduced. By deriving a critical bulk Richardson number for wintertime in high latitudes, we have extended the analysis to radiosonde data. Furthermore, we have tested the applicability of the Monin-Obukhov similarity theory to derive surface mixing layer heights based on measured surface fluxes.

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Atmospheric boundary layer structure over the Arctic Ocean during MOSAiC

Cited by 2 publications

References 0 publications

On the Mechanisms Driving Latent Heat Flux Variations in the Northwest Tropical Atlantic

On the Mechanisms Driving Latent Heat Flux Variations in the Northwest Tropical Atlantic

Determining the surface mixing layer height of the Arctic atmospheric boundary layer during polar night in cloudless and cloudy conditions

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