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NASA satellites (Figure 13) and numerous instruments provide high accuracy, stable, circum-Arctic measurements for ocean and sea ice observing, including surface vector winds over the ice-free ocean, sea surface temperature, marine phytoplankton and sea ice temperature. The NASA satellites and ocean and sea ice data sets include: 1. Passive microwave time series of sea ice extent begin in 1978 and are archived at NSIDC. 2. The major Synthetic Aperture Radar (SAR) time series is from the Canadian RADARSAT satellite launched in 1995. RADARSAT data of the Arctic Ocean are processed by the RGPS (RADARSAT Geophysical Processing System, yielding high-resolution charts of ice motion, age/thickness and deformation. All RGPS data are archived at the NASA-supported Alaska Satellite Facility (ASF), University of Alaska Fairbanks. 3. GRACE is a joint NASA/German mission that measures the changes in gravity associated with the changing mass of the ocean, land, and ice sheets. In experimental measurements, GRACE has measured the changes of mass associated with the shift of ocean currents in the Arctic Ocean. 4. The ICESat satellite is in a high latitude orbit (86°N) and can determine the free surface height of the Arctic Ocean up to that latitude. These laser measurements can be used to determine the geostrophic flow. ICESat also measures the height of the snow/air interface of the sea ice, which can be used to estimate sea ice thickness when combined with other data, e.g., snowfall and ice motion, or radar altimeter measurements of the sea ice freeboard. 5. Sea surface temperature (SST) and ice surface temperature (IST) are measured by NASA with the MODIS instrument aboard the Aqua and Terra satellites. The AMSR-E instrument on Aqua measures all-weather sea surface temperature. The follow-on instrument to MODIS is the Visible Infrared Imaging Radiometer Suite (VIIRS), scheduled for launch in 2010 on NPP (NPOESS Preparatory Project). The NPP follow-on satellite is the NPOESS (National Polar-orbiting Environmental Satellite System) series beginning in 2013. 6. Satellite-derived ocean color is used in combina-tion with environmental data to provide primary productivity. NASA currently provides ocean color from observations taken by the MODIS instrument on Aqua. Under present plans, the MODIS replacement is VIIRS on the NPP and NPOESS satellites. Because VIIRS on NPP is not expected to yield the same high quality of ocean color measurements as MODIS, there may be a gap in the high accuracy of these measurements.
The USCG contributes to ocean and sea ice observa¬tions through a number of activities. First, USCG supports Arctic research through its icebreaking operations. Assets include three polar class icebreak¬ers, of which HEALY operates in the Arctic, POLAR SEA has recently completed drydock work, and POLAR STAR is in caretaker status pending an Administration decision on how the US can best meet polar icebreaking requirements. USCG carries out the annual International Ice Patrol (IIP). The activities of the IIP are governed by treaty and US law to encompass only those ice regions of the North Atlantic Ocean through which the major trans-Atlantic shipping lanes pass. There remain other areas of ice danger where shipping must exercise extreme caution. Information concerning ice conditions is collected primarily by air surveillance flights and from ships operating in the ice area. All iceberg data, together with ocean current and wind data, are entered into a computer model that predicts iceberg drift. Every 12 hours, the predicted iceberg locations are used to estimate the limit of all known ice. This limit, along with a few of the more critical predicted iceberg locations, is broadcast as an “Ice Bulletin” from radio stations around the US, Canada, Europe and over the Worldwide Web for the benefit of all vessels crossing the north Atlantic. In addition to the Ice Bulletin, a radio facsimile chart of the area, depicting the limits of all known ice, is broadcast twice daily. USCG has begun the Arctic Domain Awareness (ADA) program to prepare for increased maritime activity as climate changes provide greater access to the Arctic. Understanding the Arctic Maritime Do¬main is part of a DOD and DHS effort to improve Maritime Domain Awareness (MDA) by developing an effective understanding of the global maritime domain and supporting effective decision-making as outlined in the National Strategy for Maritime Security. MDA includes both environmental condi¬tions and human activities that could affect maritime safety, security, the economy or environment. As MDA is expanded to the Arctic, there are likely overlaps in resource needs and sensors that could apply to both MDA/ADA and AON, and coordina¬tion of their activities will be mutually beneficial. The IIP works closely with the National Ice Center (NIC), a multi-agency operational center operated by the US Navy, NASA, NOAA and the USCG. The NIC mission is to provide the highest quality strategic and tactical ice services tailored to meet the operational requirements of Federal agencies. The NIC also coordinates and represents the many funding agencies and partners of the US Interagency Arctic Buoy Program (IABP). NIC also funds the coordinator of the program, and NSF supports IABP data management and coordination at the University of Washington. US buoy contributions to the IABP are funded by NOAA and the Office of Naval Research (ONR). NSF supports the fabrication and deployment of drifting ice mass balance buoys by the Cold Regions Research and Engineering Laboratory (CRREL), US Army Corps of Engineers.
Both NOAA and NASA operate satellites with cover¬age of the Arctic region. The major observations and products are: 1. Daily, near real-time plots of surface, cloud, and radiative properties from AVHRR; 2. Near real-time MODIS and AVHRR polar winds; 3. Daily, near real-time plots of clear sky, low-level temperature inversions from MODIS; 4. Daily profile plots of Arctic temperature, humid-ity and winds; 5. Near-daily plots of surface winds over open water; and 6. Surface temperatures for land, sea and sea ice.
Sea ice is a dominant feature of marine ecosystems in the Arctic. Its presence directly or indirectly impacts Arctic marine ecosystems, especially on the shelves where benthic and pelagic systems are extensively coupled. If the extent and thickness of sea ice continue to decline, we predict a shift in the type of algal material reaching the benthos (from ice algae to phytoplankton), which will potentially impact the food requirements of the benthos. We have several pieces of evidence showing that both types of ice algae (below-ice ice algae dominated by Melosira arctica and within-ice ice algae dominated by Nitzchia frigida) presently reach the benthos in significant quantities. What we don’t know, and what we propose to address is: “What is the digestibility of ice algae and phytoplankton-derived organic matter by the Arctic macrobenthos?” From the perspective of a macrofaunal organism, digestibility includes three separate components: 1) selection (is encountered organic material ingested or rejected?); 2) absorption (is ingested organic material absorbed during passage through the gut, or does it get egested in the feces?); and 3) assimilation (is absorbed organic material assimilated into biomass?). We propose a series of hypotheses to guide our assessment of digestibility: H1: There is no difference in the quality of ice algae and phytoplankton as food for benthic organisms. H1i: There is no difference in the long-term assimilation of ice algae and phytoplankton by benthic organisms of different trophic groups (suspension feeders, deposit feeders, omnivores). H1ii: There is no difference in the short-term absorption efficiency among different trophic groups feeding on phytoplankton and ice algae. H2: The response of benthic organisms to ice algae and phytoplankton as food sources is the same when assessed on a Pan-Arctic scale. Assessment of long-term assimilation of the various types of algae (within-ice ice algae; below-ice ice algae; and phytoplankton) will be conducted by determining lipid biomarkers and their isotopic ratios, and by determining CHN and protein signatures of organisms collected during all aspects of the work (summer ’02; spring ’03; fall ’03; and summer ’04 in both Norway and Kotzebue, Alaska). Assessment of short-term absorption will first use the ash-ratio method in a whole core delivery experiment. Following the whole-core experiments, dominant taxa from each trophic group will be identified and used in a comparison of 1) absorption efficiencies as calculated by the ash-ratio method, and 2) carbon retention efficiencies as calculated using a pulse-chase radiotracer approach. Finally, we will repeat the dominant taxa absorption efficiency experiments in both Svalbard, Norway at the Ny Ålesund lab and in Kotzebue Sound, Alaska.
Measurements of the changes when growing ice is depositing salt into the fjord.
The Submarine Operational And Research Environmental Database (SOARED)is comprised of a fixed relational environmental database using unclassified data collected during the Science Ice Exercises (SCICEX) during the past several years. It also includes publicly accessible gridded historical sound velocity, temperature and salinity data from 1900 from the US National Oceanographic Data Center. This project is a demonstration system to show ways to retrieve and analyze sound velocity, temperature and salinity profiles, bathymetry and ice thickness data using a mouse-driven GIS-based query.
Our broad area of enquiry is the role of polar regions in the global energy and water cycles, and the atmospheric, oceanic and sea ice processes that determine that role. The primary importance of our investigation is to show how these polar processes relate to global climate.
Our central geophysical objective is to determine how sea ice and the polar oceans respond to and influence the large-scale circulation of the atmosphere. Our primary technical objective is to determine how best to incorporate satellite measurements in an ice/ocean model.
The project consists of two parts: the generation of a data set of sea ice extents and areas, and associated scientific analyses. The objective of the first part is to produce a 30-year, research quality sea ice data set for climate change studies. The data set will build on an existing 18-year data set derived from satellite passive-microwave observations and currently archived at the National Snow and Ice Data Center in Boulder, CO. We will extend this data set by using historical data from the 1970's from the National Ice Center and new data from DMSP Special Sensor Microwave Imagers and the upcoming EOS-PM Advanced Microwave Scanning Radiometer. These data sets will be cross-calibrated to ensure a consistent 30-year data set following methods developed earlier and based on matching the geophysical parameters during periods of sensor overlap. The principal products will be Arctic and Antarctic sea ice extents and areas, derived from sea ice concentration maps. The second part of the proposal will center on the analysis and use of the 30-year data set. The science objectives are (1) to define and explain the hemispheric, regional, seasonal, and interannual variabilities and trends of the Arctic and Antarctic sea ice covers and (2) to understand any observed hemispheric asymmetries in global sea ice changes. Hemispheric sea ice cover asymmetries have been found in the existing 18-year record and have also been suggested from some model experiments simulating future conditions assuming a gradual increase in atmospheric CO2. We will examine the proposed 30-year record to determine the degree and nature of the hemispheric asymmetry in it and to place the sea ice observations in the context of other climate variables through comparisons with simulations from the NOAA Geophysical Fluid Dynamics Laboratory and Hadley Centre climate models.