Within the last 25 years a remarkable increase of the Arctic near–surface air temperature exceeding the global warming by a factor of two has been observed. This phenomenon is commonly referred to as Arctic Amplification. The warming results in rather dramatic changes of a variety of Arctic climate parameters. For example, the Arctic sea ice has declined significantly. To study processes leading to Arctic Amplification we combine the scientific expertise and competency of three German universities (Leipzig, Bremen, Cologne) and two non–university research institutes (AWI, TROPOS) in the framework of a Transregional Collaborative Research Centre TR 172 (http://ac3-tr.de/) funded by the German Research Foundation (DFG). The first approved funding period (Jan 2016 to Dec 2019) covers the time frame of YOPP. The project will deliver a major German contribution to MOSAiC. Observations from instrumentation on satellites, aircraft, tethered balloons, research vessels, and a selected set of ground–based sites will be integrated in dedicated campaigns, as well as being combined with long–term measurements. The field studies will be conducted in different seasons and meteorological conditions, covering a suitably wide range of spatial and temporal scales. They will be performed in an international context and in close collaboration with modelling activities. The latter utilize a hierarchy of process, meso–scale, regional, and global models to bridge the spatio–temporal scales from local individual processes to appropriate climate signals. The models will serve to guide the campaigns, to analyse the measurements and sensitivities, to facilitate the attribution of the origins of observed Arctic climate changes, and to test the ability of the models to reproduce.
The project addresses the combination of earth observation (EO) data streams with a numerical model of the Arctic ocean sea-ice system using advanced data assimilation techniques. The team proposes to construct a highly flexible system for Arctic Mission Benefit Analysis (ArcMBA) that evaluates in a mathematically rigorous fashion the observational constraints through individual and groups of EO (and in situ) data products in an advanced data assimilation system. A+5 fits to the YIOO objective on the improvement of polar prediction capabilities on daily to seasonal time scales.
The project seeks to improve our understanding of physical processes in the Arctic and specifically to explore what it would take to reduce the risk of summer sea-ice completely disappearing within this century. The tools to achieve this will be improved modeling across the scales from hemispheric to local and especially for the surface energy balance and clouds, and improved process-level research-grade observations by building a semipermanent atmospheric observatory on the Swedish icebreaker Oden.
Aerosol-cloud interactions are the least understood anthropogenic influence on climate change (IPCC, 2013). A major cause of this limited understanding is the poorly quantified state of aerosols in the pristine preindustrial atmosphere, which defines the baseline against which anthropogenic effects are calculated. The uncertainty in aerosol induced radiative forcing (± 0.7 from a mean of -0.55 W/m2) is twice the uncertainty for CO2 (± 0.35, mean +1.68 W/m2). Also, models grossly underestimate cloud solar reflectance there, by as much as 30 W/m2 during summer. We suspect it partly being due to poor representation of aerosol-cloud interactions.
This project aims at reducing the uncertainty in the effects of aerosols on climate change by exploring preindustrial-like conditions which can almost only be found in the Southern Ocean. To achieve this, we will conduct ship-based measurements of aerosol microphysical and chemical characteristics as well as measurements of trace gases modulating particle characteristics and combine these with on-board remote sensing and satellite data of clouds to evaluate global climate models.
The Southern Ocean is the most pristine aerosol environment on Earth, but almost the entire region remains unsampled. The ACE expedition from December 2016 to March 2017 provides a unique and unprecedented opportunity to prove or dismiss this hypothesis.
A suite of cloud, aerosol and radiation instruments will be deployed to Macquarie Island (54°S) Davis (69°S), and onboard the Australian icebreaker (43°S - 69°S). The data collected will be used to validate satellite cloud retrievals; evaluate weather forecasting and climate models; and aid in model development. ARM deployments to Macquarie Island (MICRE, 2016-18) and onboard the Australian icebreaker (MARCUS, summer 2017-18 season) are a key component of this research project.
A high-resolution coupled atmosphere-cryosphere-ocean model will be developed and used in the Adélie Land area, Antarctica to evaluate the impacts of the high spatial and temporal resolution, explicit treatment of small-scale processes usually neglected or highly parameterized in global climate models, and coupling on the sea ice characteristics, the air-ice-ocean interactions, and the surface mass balance of the Antarctic ice sheet on daily to seasonal time scales. The effect of initial conditions on the model prediction skill will also be assessed.
ALERTNESS will significantly improve AROME Arctic, the recent entry-into-service weather forecast model system at MET Norway. It is an operational convection-permitting model system dedicated to the European Arctic and one of the core models of the Year of Polar Prediction (YOPP). The project will advance challenges unique for the Arctic: The sparse conventional observation network, exploitation of satellite observations over snow and ice, atmospheric data assimilation at high latitudes, parameterization and representation of key polar processes, and the associated representation of uncertainties. The project is led by MET Norway, with co-leads from University of Bergen, the University Centre in Svalbard (UNIS), and Uni Research.
This project builds upon an existing one being led by Atkinson. The intent is to continue working towards improved marine weather and storm information and preparedness for ocean waves, swell and storm surge for coastal communities (Ulukhaktok, Tuktoyaktuk and Sachs Harbour) and marine operations in the western Canadian Arctic.
The main focus of the project Antarctic precipitation properties from ground-based instruments (APP) is to set up an observatory for investigating precipitation in Antarctica. Characterization of effective precipitation that occurs at ground of Antarctica region, plays a crucial rules in defining and validating global climate models and numerical weather prediction model. The observatory is designed to be set up at the Italian Antarctic station Mario Zucchelli integrating the current instrumentation for weather measurements with other instruments specific for precipitation observations. In particular, a 24-GHz vertical pointing radar, Micro Rain Radar, and an optical disdrometer, Parsivel will be integrated with the advanced weather stations, radiosoundings and the ceilometer. The synergetic use of the set of instruments allows for characterizing precipitation and studying properties of Antarctic precipitation such as dimension, shapes, fall behavior, density of particles, particles size distribution, particles terminal velocity, reflectivity factor and including some information on their vertical extent. The project is for four years, it started in July 2017 and will be active until July 2020, covering the Special Observation Period (SOP) in the Southern Hemisphere of Year of Polar Predicition (YOPP) period. APP can be provide specific measurements for precipitation occurring over the Antarctic coast at high temporal resolution, in particular specific snow products such as snow rate, snow depth and their water equivalent.
APPLICATE will develop enhanced predictive capacity for weather and climate in the Arctic and beyond, and
determine the influence of Arctic climate change on Northern Hemisphere mid-latitudes, for the benefit of
policy makers, businesses and society.
Antarctic Precipitation, Remote Sensing from Surface and Space (APRES3) is a program to acquire in situ data to characterize precipitation in Antarctica (rate, size and shape of falling snow), use the data to calibrate, validate and contribute improve satellite climatology, improve cold microphysics of water condensation in meteorological and climate models, evaluate and validate the models using satellite climatology, and finally run forecasts of precipitation changes and impact on sea-level, in time to contribute IPCC6.
Interactions in the Arctic atmosphere-sea-ice-ocean system change the circulation/dynamics/heat in the ocean and lower atmosphere, and the thickness/distribution of sea-ice and snow. Autonomous, integrated atmosphere-ice-ocean buoy systems have been developed to provide year-round observations from the harsh and hard to access Arctic Ocean. In addition to giving a quasi-synoptic view on regional scales, these systems allow an in-depth study of local processes. Satellite observations allow additional synoptic insight and need to connect observational scales. Building on our expertise we propose to study key local processes involving sea-ice-atmosphere-ocean interaction in a large-scale context. In addition to synthesising existing autonomous observations and satellite data products in scientific analyses, the work will feedback with buoy-related programmes and support the upcoming international drift campaign MOSAiC. This project will support YOPP by evaluation of near-real-time observational systems in a long-term context.
Arctic ice has declined during the last decade, and possibly related unprecedented abnormal midlatitude weather has been reported. There is evidence that a more complete Arctic observing system will improve tropical cyclone track forecast in the mid latitudes. Arctic observations require urgent research efforts for effective planning to prevent or mitigate potentially large societal and economic losses.
In this project, effective observation system in the Arctic region to improve Arctic and mid-latitude extended-range forecasts will be investigated using Observing System Simulation Experiments (OSSEs). Global and Regional OSSEs and theoretical prediction can provide complementary information about requirements for future Arctic observing systems. First, OSSEs with global coverage will be conducted at relatively low resolution, and resolution will then be varied to evaluate how the observation impact depends on the model resolution and various configurations. The impact of higher resolution will be investigated with regional OSSEs with advanced physics over the Arctic.
Simulated experiments with idealized observations will be conducted in the initial stage. Idealized observations are designed based on the distribution of planned potential observing systems without current technical limitations.
The task will be accomplished by making the best use of the recently developed US operational weather forecast system including the Next Generation Global Prediction System (NGGPS). The Nature Run (NR), simulated ‘truth’ for the OSSEs, which is most suitable for this project, is being prepared.
Large investments are currently made to improve mapping, monitoring, observing and surveying capabilities in the Arctic Ocean. These new technological infrastructures widen the range of available information. This provides a basis for the growth of informed economic activities, thus stretching the boundaries of the accessible Arctic. The information systems thereby seem to play a double role. While making the Arctic more controllable and predictable, they also enlarge the potential risks and hazards associated with increasing activity. The main objective of this project is to analyze the development of information systems in the Arctic and how they affect economic decision-making. In three thematic work packages, we (1) investigate the development of Arctic information systems as socio-technical infrastructures; (2) generate deeper understanding of the complexities and challenges in the user-producer interface in Arctic information systems; (3) and explore how Arctic information systems affect economic decision-making and alters the Arctic as a zone of risk.
Arctic sea ice has undergone rapid changes in the last decade as thick, multi-year ice has been melting and replaced with thin, more dynamically-fragile first-year ice. This, coupled with a strong trend towards reduced sea-ice extent has led to a transition towards a new, blue Arctic. This brings uncertainty for atmospheric and sea-ice forecasts in the region as many aspects of air-ice coupling are poorly understood on both the small-scale and the mesoscale.
In this project, we seek to improve our understanding of the importance of air-ice coupling processes for atmospheric and sea-ice forecasts by using a hierarchy-of-coupling approach. We will use an advanced sea-ice model with a realistic rheology, NeXtSIM, in combination with the Weather Research and Forecasting model and an interfacial atmospheric boundary layer model to assess coupling processes and their importance for atmospheric and sea-ice forecasts.
A primary objective of SCAR’s expert group Antarctic Sea ice Processes and Climate (ASPeCt: http://aspect.antarctica.gov.au/) is to establish the distribution of the basic physical properties of sea ice that are important to air-sea interaction and to biological processes within the Antarctic sea-ice zone. To achieve this goal, ASPeCt has established a data-acquisition strategy of maintaining an ongoing system of quantified shipboard observations that provides statistical descriptions of sea ice and snow thickness distributions. These observations of in-situ ice characteristics, made year after year, largely during the southern spring, summer and autumn, are crucial for monitoring and understanding the maritime climate system as well as for providing verification of satellite products and model output. These observations are directly relevant to the YOPP objectives outlined in the YOPP Implementation Plan. Therefore, ASPeCt proposes to contribute its acquisition strategy and the sea-ice data so acquired, to the YOPP effort to be used, for example, for model verification and improved representation of sea ice in models.
ASPIRE will address the Antarctic atmosphere and snow. The work will result in better understanding of physical processes as well as in parameterizations and post-processing methods applicable in weather prediction.
The primary objective of AWARE on the West Antarctic Ice Sheet (WAIS) is to characterize the atmospheric and surface energy budget, and atmospheric thermodynamic structure as completely as possible with available logistics and instrumentation, in order to garner a data set that can be interpreted in the context of large-scale atmospheric dynamics to understand specific warming mechanisms over West Antarctica. The primary objectives of AWARE at McMurdo are (1) to empirically understand the unique Antarctic manifestations of mixed-phase clouds and aerosols, and their effect on the radiation budget, and (2) using the most advanced atmospheric instrumentation available, examine microphysical properties of clouds that have recently descended from the WAIS to Ross Island via the Ross Ice Shelf. Principal Investigator (PI): Dan Lubin, Scripps. D. Bromwich is one of four Co-PIs.
During the three "YOPP Special Observing Periods" we intend to launch extra radiosondes (envisaged are 4 per day) at the three AWI research platforms Neumayer (Antarctica), Polarstern (research vessel), and AWIPEV (Ny Alesund, Spitsbergen).
The West Antarctic Ice Sheet (WAIS) and the Antarctic Peninsula (AP) have been among the most rapidly warming regions on Earth, although the AP has more recently experienced a halt in warming. Despite the rapid change experienced in the WAIS and AP, knowledge of clouds is severely limited. In addition, clouds over the Southern Ocean are not reproduced accurately in climate models, with important implications for global climate modeling. We plan to measure atmospheric and low-cloud properties over the AP during Austral summers 2016/2017 (complete), 2017/2018, and 2018/2019, and over the WAIS during a short field campaign during Austral summer 2018/2019. Our goals are to improve our understanding of low-cloud properties, their impact on warming and sea ice concentration, and their representation in models. We are particularly interested in the frequency and effects of supercooled liquid cloud.
Measurements: Standard radiosoundings will be made, measuring atmospheric pressure, temperature, humidity and winds up to 20 km. To extend the time span of soundings, we are collaborating with scientists at the Korean and Chinese stations on King George Island. In addition, several soundings will include cloud sensors capable of determining cloud height, thermodynamic phase, and droplet or ice crystal size distribution. Surface-based instruments (pyrgeometer and pyranometer) will measure broadband ultraviolet/visible and infrared radiation. Furthermore, our measurements will be complemented by additional measurements made by the Antarctic Research Group of the Universidad de Santiago de Chile (USACH), including a mini-micropulse lidar, which will remotely sense cloud height and thermodynamic phase, and spectroradiometer measurements of ultraviolet and visible radiation.
CAESAR (Cold-Air outbreak Experiment in the Sub-Arctic Region) will deploy the US National Science Foundation NCAR C-130 aircraft to document convective clouds in the marine boundary layer (MBL) during cold-air outbreaks in the far northern Atlantic Ocean, in a region stretching from the Fram strait to the Barents Sea. The NCAR C-130 will be based in Kiruna, Sweden (KRN), and conduct research flights between 23 Feb and 7 April 2021. The payload will include dropsondes, the Wyoming Cloud Radar (WCR, three antennas, up/down and slant back), the Ka-band Profiling Radar (KPR), the Wyoming Cloud Lidar (WCL, up-looking), the (Multi-function Airborne Raman Lidar (MARLi), a microwave radiometer, a number of Optical Array Probes for precipitation particles, cloud particle spectrometers and total liquid/ice probes, the VCSEL water vapor sensor, several probes to measure the concentration and size distribution of aerosol, including cloud-active aerosol, several trace gas probes, as well as meteorological and eddy correlation flux sensors. CAESAR is expected to improve the understanding of aerosol-cloud-precipitation processes in mixed phase clouds, and its representation in regional and global climate models. These data are sorely needed since MBL clouds represent a significant challenge to NWP and climate models, especially in the high-latitude regions, as they generally are sub-grid-scale and fall in the gray zone where boundary-layer processes and convection are tightly coupled and cannot be parameterized independently.
CANDIFLOS will develop new parameterizations of the turbulent surface fluxes of momentum, heat, and water vapour over sea ice using in situ measurements collected over a total of 18 weeks of cruise time in the Arctic Ocean. The parameterizations will be implemented in the Met Office Unified Model, in both forecast (atmosphere only) and climate (fully coupled, Hadley Centre Global Environment Model version 3, HadGEM3) versions. The impact of the new parameterizations on the surface energy budget and sea ice will be evaluated within HadGEM3.