Towards prediction of environmental Arctic change

Our main objective is to use models of the coupled ice-ocean Arctic environment to understand the past and present sea ice and ocean states and to predict future scenarios of environmental change in the Arctic Ocean. To meet this objective we have developed a coupled ice­ ocean model of the sea ice covered northern hemisphere at 9-km and 45-level grid. The model has been spun up for 48 years. Three 24-year experiments have been completed following the spinup, all forced with realistic 1979-2002 ECMWF data but with a different surface temperature and salinity restoring times. Results from these integrations are compared to each other and to sea ice data available over this period to address the growing need for understanding the recent warming and the subsequent decrease of the Arctic Ice Pack during the late 1990s and 2000s

A New Arctic Ice-Ocean Prediction System

LONG-TERM GOALS: The long term goal of the project is to produce a new operational Arctic ice-ocean prediction system that improves on the earlier PIPS 1.0 and PIPS 2.0 systems, as measured in terms of forecasting skill.Award #: N0001499WR3013

2008 Report for the project entitled: A Comprehensive Modeling Approach Towards Understanding and Prediction of the Alaskan Coastal System Response to Changes in an Ice-diminished Arctic

LONG-TERM GOALS: Our research combines state-of-the-art regional modeling of sea ice, ocean, atmosphere and ecosystem to provide a system approach to advance the knowledge and predictive capability of the diverse impacts of changing sea ice cover on the bio-physical marine environment of coastal Alaska and over the larger region of the western Arctic Ocean. The focus of this project on seasonally ice-free Alaskan coasts and shelves is in direct support of the ‘Coastal Effects of a Diminished-ice Arctic Ocean’ and littoral studies of interest to the U.S. Navy. Given the continued warming and summer sea ice cover decrease in the Arctic during the past decades, this research will have broader and long-term impacts by facilitating studies of the potential increased exploration of natural resources along the seasonally ice-free northern Alaskan coasts and shelves and of the use of northern sea routes from the Pacific Ocean to Europe. Such activities will change the strategic importance of the entire pan-Arctic region. The research will allow a better understanding and planning of current and future operational needs in support of the continued US commercial and tactical interests in the region.Award Number: N0001407WR2029

A Comprehensive Modeling Approach Towards Understanding and Prediction

Long-Term Goals: Our research combines state-of-the-art regional modeling of sea ice, ocean, atmosphere and ecosystem to provide a system approach to advance the knowledge and predictive capability of the diverse impacts of changing sea ice cover on the bio-physical marine environment of coastal Alaska and over the larger region of the western Arctic Ocean. The focus of this project on seasonally ice-free Alaskan coasts and shelves is in direct support of the ‘Coastal Effects of a Diminished-ice Arctic Ocean’ and littoral studies of interest to the U.S. Navy. Given the continued warming and summer sea ice cover decrease in the Arctic during the past decades, this research will have broader and long-term impacts by facilitating studies of the potential increased exploration of natural resources along the seasonally ice-free northern Alaskan coasts and shelves and of the use of northern sea routes from the Pacific Ocean to Europe. Such activities will change the strategic importance of the entire pan-Arctic region. The research will allow a better understanding and planning of current and future operational needs in support of the continued US commercial and tactical interests in the region.Award Number: N0001407WR2029

Researchers explore Arctic freshwater\u27s role in ocean circulation

A critical, but insufficiently understood, component of global change is the influence of Arctic freshwater input on water mass exchange between the Arctic Ocean and Atlantic and Pacific Oceans. Four of the Earth\u27s 10 largest river systems, the Mackenzie, Ob,Yenisei, and Lena, contribute water to the Arctic shore (Figure 1) from a vast watershed that drains continental interiors. This river discharge flows into the world\u27s largest contiguous continental shelf and supplies over 50% (1823 km3 ) of the riverine input to the Arctic Ocean

Sensitivity of Arctic sea ice to variable model parameter space in Regional Arctic System Model simulations

The article of record as published may be found at https://doi.org/10.5194/egusphere-egu2020-13039EGU General Assembly 2020The Arctic climate system is very sensitive to the state of sea ice due to its role in controlling heat and momentum exchanges between the atmosphere and the ocean. However, the representation of sea ice state, its past variability and future projections in modern Earth system models (ESMs) vary widely. One of the reasons for that is strong sensitivity of ESMs to sea ice related varying parameter space. Based on limited observations, those parameters typically have a range of possible values and / or are not constant in space and time, which is a source of model uncertainties. The Regional Arctic System Model (RASM) is a limited-domain fully coupled climate model used in this study to investigate sensitivity of sea ice states to limited set of parameters. It includes the atmospheric (Weather Research and Forecasting; WRF) and land hydrology (Variable Inltration Capacity; VIC) components sharing a 50-km pan-Arctic grid. The sea ice (the version 6.0 of Los Alamos sea ice model, CICE) and ocean (Parallel Ocean Program, POP) components share a 1/12° pan-Arctic grid. In addition, a river routing scheme (RVIC) is used to represent the freshwater ux from land to ocean. All components are coupled at high frequency via the Community Earth System Model (CESM) coupler version CPL7. We have selected four parameters out of the set evaluated by Urrego-Blanco et al. (2016) and subject to their potential impact on sea ice and coupling across the atmosphere-sea ice- ocean interface. The total of 96 sensitivity simulations have been completed with fully coupled and forced RASM congurations, varying each parameter within its respective acceptable range. Using sea ice volume as a measure of sensitivity, the thermal conductivity of snow (ksno) parameter has produced the most sensitivity, in qualitative agreement with Urrego-Blanco et al. (2016). However, using dynamics related metrics, such as sea ice drift or deformation, other parameters, i.e. controlling the sea ice roughness and frictional energy dissipation, have been shown more important. Finally, dierent quantitative sensitivities to the same parameter have been diagnosed between fully-coupled and forced RASM simulations, as well as compared to the stand alone sea ice results

Evaluation of Under Sea-ice Phytoplankton Blooms in the Fully-Coupled, High-Resolution Regional Arctic System Model

First posted online: Fri, 31 Jul 2020 09:53:38 | This content has not been peer reviewed.Manuscript submitted to JGR: OceansThe article of record as published may be found at https://doi.org/10.1002/essoar.10503749.1In July 2011, observations of a massive phytoplankton bloom in the ice-covered waters of the western Chukchi Sea raised questions about the extent and frequency of under seaice blooms and their contribution to the carbon budget in the Arctic Ocean. To address some of these questions, we use the fully-coupled, high-resolution Regional Arctic System Model to simulate Arctic marine biogeochemistry over a thirty-year period. Our results demonstrate the presence of massive under sea-ice blooms in the western Arctic not only in summer of 2011 but annually throughout the simulation period. In addition, similar blooms, yet of lower magnitude occur annually in the eastern Arctic. We investigate the constraints of nitrate concentration and photosynthetically available radiation (PAR) on the initiation, evolution and cessation of under sea-ice blooms. Our results show that increasing PAR reaching the ocean surface through the sea-ice in early summer, when the majority of ice-covered Arctic waters have sufficient surface nitrate levels, is critical to bloom initiation. However, the duration and cessation of under sea-ice blooms is controlled by available nutrient concentrations as well as by the presence of sea-ice. Since modeled critical PAR level are consistently exceeded in summer only in the western Arctic, we therefore conclude that the eastern Arctic blooms shown in our simulations did not develop under sea ice, but were instead, at least in part, formed in open waters upstream and subsequently advected by ocean currents beneath the sea ice.This research was partially supported by the following: Collaborative Research: Understanding Arctic Marine Biogeochemical Response to Climate Change for Seasonal to Decadal Prediction Using Regional and Global Climate Models, Award number IAA1417888, Program NSF ARCSS; High-Latitude Application and Testing of Earth System Models Phase II, Award number IAA89243019SSC000030, Program DOERGMA; Ministry of Science and Higher Education in Poland in the frame of co-financed international project agreement Award number 3808/FAO/2017/0 RASMer.This research was partially supported by the following: Collaborative Research: Understanding Arctic Marine Biogeochemical Response to Climate Change for Seasonal to Decadal Prediction Using Regional and Global Climate Models, Award number IAA1417888, Program NSF ARCSS; High-Latitude Application and Testing of Earth System Models Phase II, Award number IAA89243019SSC000030, Program DOERGMA; Ministry of Science and Higher Education in Poland in the frame of co-financed international project agreement Award number 3808/FAO/2017/0 RASMer

On the variability of the Bering Sea Cold Pool and implications for the biophysical environment

The article of record as published may be found at http://dx.doi.org/10.1371/ journal.pone.0266180The Bering Sea experiences a seasonal sea ice cover, which is important to the biophysical environment found there. A pool of cold bottom water (<2 ?C) is formed on the shelf each winter as a result of cooling and vertical mixing due to brine rejection during the predominately local sea ice growth. The extent and distribution of this Cold Pool (CP) is largely controlled by the winter extent of sea ice in the Bering Sea, which can vary considerably and recently has been much lower than average. The cold bottom water of the CP is important for food security because it delineates the boundary between arctic and subarctic demersal fish species. A northward retreat of the CP will likely be associated with migration of subarctic species toward the Chukchi Sea. We use the fully-coupled Regional Arctic System Model (RASM) to examine variability of the extent and distribution of the CP and its relation to change in the sea ice cover in the Bering Sea during the period 1980–2018. RASM results confirm the direct correlation between the extent of sea ice and the CP and show a smaller CP as a consequence of realistically simulated recent declines of the sea ice cover in the Bering Sea. In fact, the area of the CP was found to be only 31% of the long-term mean in July of 2018. In addition, we also find that a low ice year is followed by a later diatom bloom, while a heavy ice year is followed by an early diatom bloom. Finally, the RASM probabilistic intra-annual forecast capability is reviewed, based on 31-member ensembles for 2019– 2021, for its potential use for prediction of the winter sea ice cover and the subsequent summer CP area in the Bering Sea.This work was supported by the US National Science Foundation (GEO/PLR ARCSS IAA1417888 and IAA1603602), the US Department of Energy (DOE) Regional and Global Model Analysis (RGMA) (89243019SSC0036 and DESC0014117), and the Office of Naval Research (ONR) Arctic and Global Prediction (AGP) (N0001418WX00364). The Department of Defense (DOD) High Performance Computer Modernization Program (HPCMP) provided computer resources.This work was supported by the US National Science Foundation (GEO/PLR ARCSS IAA1417888 and IAA1603602), the US Department of Energy (DOE) Regional and Global Model Analysis (RGMA) (89243019SSC0036 and DESC0014117), and the Office of Naval Research (ONR) Arctic and Global Prediction (AGP) (N0001418WX00364). The Department of Defense (DOD) High Performance Computer Modernization Program (HPCMP) provided computer resources

Intrusion of warm Bering/Chukchi waters onto the shelf in the western Beaufort Sea

Author Posting. © American Geophysical Union, 2009. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 114 (2009): C00A11, doi:10.1029/2008JC004870.Wind-driven changes in the path of warm Bering/Chukchi waters carried by the Alaska Coastal Current (ACC) through Barrow Canyon during late summer are described from high-resolution hydrography, acoustic Doppler current profiler–measured currents, and satellite-measured sea surface temperature imagery acquired from mid-August to mid-September 2005–2007 near Barrow, Alaska. Numerical simulations are used to provide a multidecadal context for these observational data. Four generalized wind regimes and associated circulation states are identified. When winds are from the east or east-southeast, the ACC jet tends to be relatively strong and flows adjacent to the shelf break along the southern flank of Barrow Canyon. These easterly winds drive inner shelf currents northwestward along the Alaskan Beaufort coast where they oppose significant eastward intrusions of warm water from Barrow Canyon onto the shelf. Because these easterly winds promote sea level set down over the Beaufort shelf and upwelling along the Beaufort slope, the ACC jet necessarily becomes weaker, broader, and displaced seaward from the Beaufort shelf break upon exiting Barrow Canyon. Winds from the northeast promote separation of the ACC from the southern flank of Barrow Canyon and establish an up-canyon current along the southern flank that is fed in part by waters from the western Beaufort shelf. When winds are weak or from the southwest, warm Bering/Chukchi waters from Barrow Canyon intrude onto the western Beaufort shelf.This work was supported in 2005 and 2006 by NSF grants OPP-0436131 and OPP-0436166. In 2007, this work received support through Woods Hole Oceanographic Institution- NOAA Cooperative Institute for Climate and Ocean Research Cooperative Agreement NA17RJ1223 and University of Alaska Fairbanks-NOAA Cooperative Institute for Arctic Research Cooperative Agreement NA17RJ1224. Additional support was provided by the James M. and Ruth P. Clark Arctic Research Initiative Fund at the Woods Hole Oceanographic Institution