First insight into thermodynamic profiles, IWV and LWP from ground-based microwave radiometers during MOSAiC

2021 ◽  
Author(s):  
Andreas Walbröl ◽  
Patrick Konjari ◽  
Ronny Engelmann ◽  
Hannes Griesche ◽  
Martin Radenz ◽  
...  
Keyword(s):  
Water Vapour ◽  
Collaborative Research ◽  
Surface Processes ◽  
Arctic Climate ◽  
The Arctic ◽  
Arctic Amplification ◽  
Feedback Mechanisms ◽  
Integrated Water Vapour ◽  
Microwave Radiometers ◽  
Insight Into

<p>The Arctic is currently experiencing a more rapid warming compared to the rest of the<br>world. This phenomenon, known as Arctic Amplification, is the result of several processes.<br>Within the Collaborative Research Centre on Arctic Amplification: Climate Relevant Atmospheric<br>and Surface Processes and Feedback Mechanisms (AC)3, our research focuses<br>on the influence of water vapour, the strongest greenhouse gas. The collection of data<br>about water vapour is essential to understand its impact on Arctic Amplification. Over<br>the past decades, a positive trend in integrated water vapour in the Arctic has been<br>identified using radiosondes and reanalyses for certain regions and seasons. However, inconsistent<br>magnitudes of the moistening trend in the reanalyses cause the need of a more<br>thorough investigation. While radiosondes offer precise measurements of thermodynamic<br>(temperature and humidity) profiles, they fail to capture the variability of water vapour<br>because of the low sampling rate (two to four sondes per day) and spatial coverage. To<br>obtain a more complete picture of water vapour variability, remote sensing instruments<br>(satellite- and ground-based) are used. Microwave radiometers (MWRs) onboard polar<br>orbiting satellites allow the coverage of the entire Arctic but suffer from uncertainties<br>related to surface emission. Observations at the surface gathered during the Multidisciplinary<br>drifting Observatory for the Study of Arctic Climate (MOSAiC) campaign can<br>serve as reference measurements in the central Arctic for the assessment of water vapour<br>products from reanalyses, models and satellite retrievals.<br><br>In this study, we give a first insight into the variability of integrated water vapour (IWV),<br>liquid water path (LWP) and thermodynamic profiles retrieved from two ground-based<br>MWRs onboard the research vessel Polarstern throughout the MOSAiC campaign. The<br>first radiometer is a standard low frequency HATPRO system and the other one is the<br>high-frequency MiRAC-P, which is particularly suited for low water vapour contents. The<br>retrieved quantities are compared with radiosonde measurements. A first analysis reveals<br>that the IWV is very well captured by the MWR measurements. Over the observation<br>period (October 2019 - October 2020), a large variety of meteorological conditions occurred.<br>Besides the considerable seasonal cycle, which is especially interesting because of<br>the contrast between polar night and polar day, several synoptic events contribute to the<br>variety of conditions, which will be highlighted as well.</p><p><br>We gratefully acknowledge the funding by the Deutsche Forschungsgemeinschaft (DFG, German Research<br>Foundation) — Project 268020496 — TRR 172, within the Transregional Collaborative Research Center<br>"Arctic Amplification: Climate Relevant Atmospheric and Surface Processes, and Feedback Mechanisms<br>(AC)3". Data used in this manuscript was produced as part of the international Multidisciplinary drifting<br>Observatory for the Study of the Arctic Climate (MOSAiC) with the tag MOSAiC20192020 and the<br>Polarstern expedition AWI_PS122_00.</p>

Evaluating atmospheric rivers and their influence on precipitation in the Arctic - comparing observational with reanalysis data

2021 ◽  
Author(s):  
Melanie Lauer ◽  
Annette Rinke ◽  
Irina Gorodetskaya ◽  
Susanne Crewell
Keyword(s):  
Sea Ice ◽  
Water Vapour ◽  
Moisture Transport ◽  
Collaborative Research ◽  
Surface Processes ◽  
Research Center ◽  
The Arctic ◽  
Arctic Amplification ◽  
Feedback Mechanisms ◽  
Atmospheric Rivers

<p>The Arctic as a whole has been experiencing significant warming and moistening with several potential factors at play. In general, the warming amplifies the Arctic hydrological cycle. There are two processes which could affect the water vapour content in the Arctic. These are the enhanced local evaporation due to reduced sea-ice concentration and extent and the modified poleward moisture transport from lower latitudes due to changing circulation patterns. An important contribution to the total poleward moisture transport comes from Atmospheric rivers (ARs). ARs have rare occurrence but are associated with anomalously high moisture transport compared to tropical cyclones. ARs are typically associated with not only moisture but also with significant heat advection. They can bring precipitation as rain and/or snow. Moreover, additional feedbacks can occur: the warming effect of the ARs on the surface, coupled with rain lowering surface albedo, can cause thinning and melting of Arctic sea ice and snow. This, in turn, could increase the relative role of the local evaporation compared to the moisture transported from lower latitudes.</p><p>In this study, we investigate the relationship between the poleward moisture transport by ARs and the precipitation in the Arctic. The focus is on AR events during the ACLOUD (May/June 2017) and AFLUX (March/April 2018) campaign within the Collaborative Research Center “Arctic Amplification: Climate Relevant Atmospheric and Surface Processes, and Feedback Mechanisms (AC)<sup>3</sup>”. For these campaigns, existing AR catalogues with the input of ERA5 reanalyses are used to detect AR events. Six ARs are detected: two coming from Siberia and four from the Atlantic.</p><p>These AR events are analysed in terms of the macro- and microphysical precipitation properties, including frequency, intensity, and type of precipitation (rain or snow).  For this purpose, we use ERA5 reanalyses data for the water vapour transport, precipitation amount and type, rain and snow profiles (convective, large-scale, total), as well as vertical profile of hydrometeors. Reanalysis products are evaluated using a set of observational data (satellite data and ground-based remote sensing measurements). This new multi-parameter, multi-dataset set will allow to investigate the occurrence of ARs and its influence on precipitation in the Arctic for the last decades.</p><p> </p><p>“We gratefully acknowledge the funding by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) –Projektnummer 268020496 –TRR 172, within the Transregional Collaborative Research Center “ArctiC Amplification: Climate Relevant Atmospheric and SurfaCe Processes, and Feedback Mechanisms (AC)3.“</p>

scholarly journals Effects of Global Warming on the Poleward Heat Transport by Non-Stationary Large-Scale Atmospheric Eddies, and Feedbacks Affecting the Formation of the Arctic Climate

2021 ◽  
Vol 9 (8) ◽  
pp. 867
Author(s):  
Sergei Soldatenko
Keyword(s):  
Global Warming ◽  
Heat Transport ◽  
Large Scale ◽  
Arctic Sea Ice ◽  
Arctic Climate ◽  
The Arctic ◽  
Arctic Amplification ◽  
Near Surface ◽  
Feedback Mechanisms ◽  
Arctic Sea

It is a well-known fact that the observed rise in the Arctic near-surface temperature is more than double the increase in global mean temperature. However, the entire scientific picture of the formation of the Arctic amplification has not yet taken final shape and the causes of this phenomenon are still being discussed within the scientific community. Some recent studies suggest that the atmospheric equator-to-pole transport of heat and moisture, and also radiative feedbacks, are among the possible reasons for the Arctic amplification. In this paper, we highlight and summarize some of our research related to assessing the response of climate in the Arctic to global warming and vice versa. Since extratropical transient eddies dominate the meridional transport of sensible and latent heat from low to high latitudes, we estimated the effect of climate change on meridional heat transport by means of the β-plane model of baroclinic instability. It has been shown that the heat transport from low and middle latitudes to the Arctic by large scale transient eddies increases by about 9% due to global warming, contributing to the polar amplification—and thereby a decrease in the extent—of the Arctic sea, which, in turn, is an important factor in the formation of the Arctic climate. The main radiative feedback mechanisms affecting the formation of the Arctic climate are also considered and discussed. It was emphasized that the influence of feedbacks depends on a season since the total feedback in the winter season is negative, while in the summer season, it is positive. Thus, further research is required to diminish the uncertainty regarding the character of various feedback mechanisms in the shaping of the Artic climate and, through that, in predicting the extent of Arctic sea ice.

scholarly journals Investigation of Arctic middle-atmospheric dynamics using 3 years of H<sub>2</sub>O and O<sub>3</sub> measurements from microwave radiometers at Ny-Ålesund

2019 ◽  
Author(s):  
Franziska Schranz ◽  
Brigitte Tschanz ◽  
Rolf Rüfenacht ◽  
Klemens Hocke ◽  
Mathias Palm ◽  
...  
Keyword(s):  
Water Vapour ◽  
Middle Atmosphere ◽  
Microwave Radiometer ◽  
Polar Vortex ◽  
The Arctic ◽  
High Time Resolution ◽  
Middle Atmospheric Dynamics ◽  
Wind Profiles ◽  
Microwave Radiometers

Abstract. We use 3 years of water vapour and ozone measurements to analyse dynamical events in the polar middle atmosphere such as sudden stratospheric warmings (SSW), polar vortex shifts, water vapour descent rates and periodicities. The measurements were performed with the two ground-based microwave radiometers MIAWARA-C and GROMOS-C which are co-located at the AWIPEV research base at Ny-Ålesund, Svalbard (79° N, 12° E) since September 2015. The almost continuous datasets of water vapour and ozone are characterised by a high time resolution in the order of hours. A thorough intercomparison of these datasets with models and measurements from satellite, ground-based and in-situ instruments was performed. In the upper stratosphere and lower mesosphere the MIAWARA-C profiles agree within 5 % with SD-WACCM simulations and ACE-FTS measurements whereas AuraMLS measurements show an average offset of 10–15 % depending on altitude but constant in time. Stratospheric GROMOS-C profiles are within 5 % of the satellite instruments AuraMLS and ACE-FTS and the ground-based microwave radiometer OZORAM which is also located at Ny-Ålesund. During these first three years of the measurement campaign typical phenomena of the Arctic middle atmosphere took place and we analysed their signatures in the water vapour and ozone datasets. Inside of the polar vortex in autumn we found the descent rate of mesospheric water vapour to be 435 m/day on average. In early 2017 distinct increases in mesospheric water vapour of about 2 ppm were observed when the polar vortex was displaced and midlatitude air was brought to Ny-Ålesund. Two major sudden stratospheric warmings took place in March 2016 and February 2018 where ozone enhancements of up to 4 ppm were observed. The zonal wind reversals accompanying a major SSW were captured in the GROMOS-C wind profiles which are retrieved from the ozone spectra. After the SSW in February 2018 the polar vortex re-established and the water vapour descent rate in the mesosphere was 355 m/day. In the water vapour and ozone time series signatures of atmospheric waves with periods close to 2, 5, 10 and 16 days were found.

scholarly journals Investigation of Arctic middle-atmospheric dynamics using 3 years of H<sub>2</sub>O and O<sub>3</sub> measurements from microwave radiometers at Ny-Ålesund

2019 ◽  
Vol 19 (15) ◽  
pp. 9927-9947 ◽  
Author(s):  
Franziska Schranz ◽  
Brigitte Tschanz ◽  
Rolf Rüfenacht ◽  
Klemens Hocke ◽  
Mathias Palm ◽  
...  
Keyword(s):  
Water Vapour ◽  
Middle Atmosphere ◽  
Microwave Radiometer ◽  
Polar Vortex ◽  
Atmospheric Composition ◽  
The Arctic ◽  
High Time Resolution ◽  
Mean Meridional Circulation ◽  
Wind Profiles ◽  
Microwave Radiometers

Abstract. We used 3 years of water vapour and ozone measurements to study the dynamics in the Arctic middle atmosphere. We investigated the descent of water vapour within the polar vortex, major and minor sudden stratospheric warmings and periodicities at Ny-Ålesund. The measurements were performed with the two ground-based microwave radiometers MIAWARA-C and GROMOS-C, which have been co-located at the AWIPEV research base at Ny-Ålesund, Svalbard (79∘ N, 12∘ E), since September 2015. Both instruments belong to the Network for the Detection of Atmospheric Composition Change (NDACC). The almost continuous datasets of water vapour and ozone are characterized by a high time resolution of the order of hours. A thorough intercomparison of these datasets with models and measurements from satellite, ground-based and in situ instruments was performed. In the upper stratosphere and lower mesosphere the MIAWARA-C water vapour profiles agree within 5 % with SD-WACCM simulations and ACE-FTS measurements on average, whereas AuraMLS measurements show an average offset of 10 %–15 % depending on altitude but constant in time. Stratospheric GROMOS-C ozone profiles are on average within 6 % of the SD-WACCM model, the AuraMLS and ACE-FTS satellite instruments and the OZORAM ground-based microwave radiometer which is also located at Ny-Ålesund. During these first 3 years of the measurement campaign typical phenomena of the Arctic middle atmosphere took place, and we analysed their signatures in the water vapour and ozone measurements. Two major sudden stratospheric warmings (SSWs) took place in March 2016 and February 2018 and three minor warmings were observed in early 2017. Ozone-rich air was brought to the pole and during the major warmings ozone enhancements of up to 4 ppm were observed. The reversals of the zonal wind accompanying a major SSW were captured in the GROMOS-C wind profiles which are retrieved from the ozone spectra. After the SSW in February 2018 the polar vortex re-established and the water vapour descent rate in the mesosphere was 355 m d−1. Inside of the polar vortex in autumn we found the descent rate of mesospheric water vapour from MIAWARA-C to be 435 m d−1 on average. We find that the water vapour descent rate from SD-WACCM and the vertical velocity w‾* of the residual mean meridional circulation from SD-WACCM are substantially higher than the descent rates of MIAWARA-C. w‾* and the zonal mean water vapour descent rate from SD-WACCM agree within 10 % after the SSW, whereas in autumn w‾* is up to 40 % higher. We further present an overview of the periodicities in the water vapour and ozone measurements and analysed seasonal and interannual differences.

scholarly journals Improved water vapour retrieval from AMSU-B and MHS in the Arctic

2020 ◽  
Vol 13 (7) ◽  
pp. 3697-3715
Author(s):  
Arantxa M. Triana-Gómez ◽  
Georg Heygster ◽  
Christian Melsheimer ◽  
Gunnar Spreen ◽  
Monia Negusini ◽  
...  
Keyword(s):  
Water Vapour ◽  
In Situ Measurements ◽  
The Arctic ◽  
Retrieval Algorithm ◽  
Polar Regions ◽  
Climate Trends ◽  
Arctic Conditions ◽  
Integrated Water Vapour ◽  
Ice Content

Abstract. Monitoring of water vapour in the Arctic on long timescales is essential for predicting Arctic weather and understanding climate trends, as well as addressing its influence on the positive feedback loop contributing to Arctic amplification. However, this is challenged by the sparseness of in situ measurements and the problems that standard remote sensing retrieval methods for water vapour have in Arctic conditions. Here, we present advances in a retrieval algorithm for vertically integrated water vapour (total water vapour, TWV) in polar regions from data of satellite-based microwave humidity sounders: (1) in addition to AMSU-B (Advanced Microwave Sounding Unit-B), we can now also use data from the successor instrument MHS (Microwave Humidity Sounder), and (2) artefacts caused by high cloud ice content in convective clouds are filtered out. Comparison to in situ measurements using GPS and radiosondes during 2008 and 2009, as well as to radiosondes during the N-ICE2015 campaign and to ERA5 reanalysis, show the overall good performance of the updated algorithm.

scholarly journals Experimental total uncertainty of the derived GNSS-integrated water vapour using four co-located techniques in Finland

2018 ◽  
Author(s):  
Ermanno Fionda ◽  
Maria Cadeddu ◽  
Vinia Mattioli ◽  
Rosa Pacione
Keyword(s):  
Water Vapour ◽  
Arctic Region ◽  
The Other ◽  
Gps Receiver ◽  
Scientific Software ◽  
Total Uncertainty ◽  
Integrated Water Vapour ◽  
Atmospheric Radiation Measurement ◽  
Biogenic Aerosols ◽  
Microwave Radiometers

Abstract. In this work, we examine data from a Global Positioning System (GPS) ground-based receiver, two co-located ground-based microwave radiometers (MWRs), and radiosondes (RAOBs) to characterize the uncertainties associated with integrated water vapour (IWV) values estimated from the GPS in a sub-Arctic climate region. The experiment was carried out during the Biogenic Aerosols–Effects on Clouds and Climate research campaign conducted using the Atmospheric Radiation Measurement Program's second Mobile Facility (AMF2) in collaboration with the University of Helsinki. The GPS receiver was located about 20 km away from the AMF2 instruments (radiometers and RAOB). The GPS data were processed in Precise Point Positioning mode using the state-of-the-art scientific software GIPSY-OASIS II. Differences between the GPS-derived IWV and that derived from the other three instruments are analysed in terms of bias, standard deviation, and root-mean-square error (RMSE). The availability of three co-located, independently calibrated systems (two MWRs and one RAOB) allows us to isolate issues that may be specific to a single system and to isolate the effects of the distance between the GPS receiver and the remaining instruments. The representativeness error due to the 20-km distance between the GPS and the other systems is of the order of 0.6–1.5 kg/m2 and in this study is the dominant effect when the IWV is higher than 20 kg/m2. The RMSE between the instruments shows that in the sub-Arctic region, when the IWV variability is less than 20 kg/m2, the GPS agrees with other instruments to within 0.5 kg/m2. When the variability of water vapour in the 20-km region is higher than 20 kg/m2, mostly in the summer months, the GPS agrees with other instruments within 1–2 kg/m2.

scholarly journals The Arctic Cloud Puzzle: Using ACLOUD/PASCAL Multiplatform Observations to Unravel the Role of Clouds and Aerosol Particles in Arctic Amplification

2019 ◽  
Vol 100 (5) ◽  
pp. 841-871 ◽  
Author(s):  
Manfred Wendisch ◽  
Andreas Macke ◽  
André Ehrlich ◽  
Christof Lüpkes ◽  
Mario Mech ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Aerosol Particles ◽  
Surface Air Temperature ◽  
Field Studies ◽  
Surface Processes ◽  
The Arctic ◽  
Arctic Amplification ◽  
Arctic Boundary Layer ◽  
Near Surface ◽  
Airborne Measurements

AbstractClouds play an important role in Arctic amplification. This term represents the recently observed enhanced warming of the Arctic relative to the global increase of near-surface air temperature. However, there are still important knowledge gaps regarding the interplay between Arctic clouds and aerosol particles, and surface properties, as well as turbulent and radiative fluxes that inhibit accurate model simulations of clouds in the Arctic climate system. In an attempt to resolve this so-called Arctic cloud puzzle, two comprehensive and closely coordinated field studies were conducted: the Arctic Cloud Observations Using Airborne Measurements during Polar Day (ACLOUD) aircraft campaign and the Physical Feedbacks of Arctic Boundary Layer, Sea Ice, Cloud and Aerosol (PASCAL) ice breaker expedition. Both observational studies were performed in the framework of the German Arctic Amplification: Climate Relevant Atmospheric and Surface Processes, and Feedback Mechanisms (AC)3 project. They took place in the vicinity of Svalbard, Norway, in May and June 2017. ACLOUD and PASCAL explored four pieces of the Arctic cloud puzzle: cloud properties, aerosol impact on clouds, atmospheric radiation, and turbulent dynamical processes. The two instrumented Polar 5 and Polar 6 aircraft; the icebreaker Research Vessel (R/V) Polarstern; an ice floe camp including an instrumented tethered balloon; and the permanent ground-based measurement station at Ny-Ålesund, Svalbard, were employed to observe Arctic low- and mid-level mixed-phase clouds and to investigate related atmospheric and surface processes. The Polar 5 aircraft served as a remote sensing observatory examining the clouds from above by downward-looking sensors; the Polar 6 aircraft operated as a flying in situ measurement laboratory sampling inside and below the clouds. Most of the collocated Polar 5/6 flights were conducted either above the R/V Polarstern or over the Ny-Ålesund station, both of which monitored the clouds from below using similar but upward-looking remote sensing techniques as the Polar 5 aircraft. Several of the flights were carried out underneath collocated satellite tracks. The paper motivates the scientific objectives of the ACLOUD/PASCAL observations and describes the measured quantities, retrieved parameters, and the applied complementary instrumentation. Furthermore, it discusses selected measurement results and poses critical research questions to be answered in future papers analyzing the data from the two field campaigns.

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