Expressions of Intent for IPY 2007-2008 Activities

Expression of Interest Details

PROPOSAL INFORMATION

IMPROVEMENT OF REGIONAL ALTIMETER CORRECTIONS AND TRACKING OF EDDIES IN THE HIGH-LATITUDE SOUTHERN OCEAN  (IRACETSO)

Outline
THE SOUTHERN OCEAN AND THE GLOBAL CLIMATE The main circulation feature in the Southern Ocean is a westward continuous flow around Antarctica known as the Antartic Circumpolar Current (ACC). The northern part of this region is known to consist of a series of areas of convergences named the Antarctic Polar Frontal Zone (APFZ), with fronts associated to strong zonal current jets with velocities between 0.5 and 1 m/s. The flow within the APFZ is complex, with many eddies and meanders that moves the colder Antarctic water masses southward and northward. This mechanism has an important influence in the global climate. The eddies in Southern Ocean, crossing the Arc of Scotia towards the Patagonian shelf, play an important role in the global climate. Its dynamics structure in depth and its ocean–atmosphere interactions are an important tool to know the heat exchange mechanism and its effects over the global climate evolution. About the possibility to estimate the climate change from sea level records, traditionally the global sea level change has been measured from tidal gauges. However their fundamental problem is that the measurements are always referred to a fixed crustal reference point and the records are no very useful for climate change studies since the variable of interest is the sea global change without really accurate crustal models. The resulting signal appears unresolved. In this sense, the direct monitoring of the geocentric location of tidal gauges, using space geodetic techniques, clearly warranty the link of the tidal sites to the global reference systems. THE ACCURACY LIMITS IN ALTIMETER SATELLITE OBSERVATIONS A satellite altimeter is a radar that measures the range from the radar antenna to the ocean surface. The required accuracy is dependant on the phenomenon of interest, generally an overall accuracy better than 5 cm is required to be useful, for the observation of the possible changes in the dynamic sea surface elevation and its applications to ocean dynamics and mean sea level trend. Satellite altimeters provide a measure of the absolute sea level referred to a reference frame realised through the whole satellite tracking stations, whose origin coincides with the earth’s centre of masses. However, local errors in the satellite orbit and modelling of the geophysical corrections militate against the sea level rate determinations. The possibility of its applications to the study of the global climate change will be in the understanding and capacity to modelize accurately all physical corrections that regionally needs to be applied to the altimeter range measurements. Up to date, the geophysical corrections applied have been made using global models, frequently wrong when applying to some regional areas with singular local characteristics or with low density of satellite tracking stations, as happens in the Southern Ocean surrounding the Antarctic continent. OBJECTIVES One of the main problems to use satellite altimetry in the Antarctic seas, and mainly in the ACC and Patagonian Self areas is the low quality of geophysical corrections applied in this singular area. One of basic objectives of the present proposal is to improve, regionally, the geophysical models of these corrections; applying the local models to the Topex-Poseidon, ERS and Jason satellite data sets for tracking the eddies found in the area Patagonian Shelf, Drake Passage and Bransfied Sea also detected by radiometric methods. The aim of present proposal is: 1-Use the Topex/Poseidon, ERS and Jason satellites altimeter time series data, together with local geomagnetic and meteorological records, and tide gauges data at selected cross over points locations in the area, to improve regionally the altimeter geophysical corrections in the area of Drake Passage, Scotia Arc, Brandsfield Sea and Patagonia shelf (Sea State Bias, Inverse barometer, atmospheric and tidal corrections) 2-Use the altimeters and tide gauges records at selected cross over points to develop a fundamental tidal constituent propagation model in the area and the comparison with the global tidal models. Tides will be computed from the orthotides approach and a hydrodynamical interpolation model will be developed to extent the solution to the whole proposed area, studying the non-linear generation of minor tidal waves. With this, it will be possible to obtain accurate tidal charts and accurate tidal corrections for the altimeter data. 3-Use of all available altimeter data (with regional geophysical corrections applied), SAR and the radiometer images to detect and track eddies crossing the Drake Passage, Scotia Arc and Patagonian Shelf since1992, using the CTD records, available in the World Data Centres, to study the structure in depth of the possible eddies detected with spatial techniques. 4-Use the Spanish Oceanographic Vessel Hesperides transect to the Antarctica, to perform CTD soundings in selected places where eddies are detected by spatial techniques. 5-Compute the mean sea level tendencies in the area and its relationship with possible regional changes in the ocean dynamic 6-Use the altimeter data, the tidal gauge deployed at selected satellite cross over points, the tidal gauge records in Antarctic bases, the tidal propagation models and the GPS local observations to calibrate the satellite altimeter.

What significant advance(s) in relation to the IPY themes and targets can be anticipated from this project?
Theme #1 To determine the present environmental status of the polar regions by quantifying their spatial and temporal variability. A key output of the IPY 2007-2008 will be:- To document the contemporary environmental status of the Polar Regions, quantifying their spatial and temporal variability and characterizing present day processes. To determine the spatial and short-term temporal variability of the climate and environment in the Polar Regions will address questions such as: What is the status of the high latitude ocean circulation and composition? The direct measurement of large scale ocean currents with the deployments of current meter arrays is difficult and expensive on basin scales. Since large-scale currents are in quasi-geostrophic balance, the surface geostrophic current can be computed from the deviation of sea level from the equi-geopotential surface, the marine geoid, at the ocean surface. The proposal pretends to compute new regional satellite geophysical corrections to improve the altimeter satellite accuracy to measure, in the Antarctic region, the sea level from space. These improvements will allow a better determination of global surface geostrophic ocean circulation and its variability in the geophysical complex area of arc of Scotia, Patagonian Self region. Repeated altimetry observations of sea level at the same locations can resolve the variability of surface geostrophic currents, without the requirement of an accurate geoid model. One of the corrections applied to satellite altimeter are related with the global tidal models that to some extend must be put in doubt in the Patagonian Self and Arc of Scotia areas. Theme #2 To quantify, and understand, past and present environmental and human change in the polar regions in order to improve predictions How are climate, environment, and ecosystems in the Polar Regions (including high latitude oceans) changing? What are the inter-hemispheric connections in these changes? In the Arc of Scotia Weddell Sea interface there are some geophysical mapping of key ocean gateways controlling roles in the cooling of the polar regions and represent fundamental boundary conditions for the polar environment today. About the heat balance in the Antarctic Ocean must be remembered that in the Southern Ocean both, heat and water seasonal fluxes, are strongly influenced by the presence of ice in the Seasonal Sea Ice area (SSI). The large expansion of ice surface reduces the exchanges of heat, mass and momentum between ocean and atmosphere and reduces the amount of solar radiation absorbed at the surface, with an important effect over the Southern Ocean system. It is also known, from the historical hydrographic data, that most of the bottom water and much of the intermediate water of the world ocean is formed around Antarctica. Water mass characteristics acquired near the surface in the Southern Ocean can be traced at depth to high latitudes in the northern hemisphere in all ocean basins. The cooling required for surface waters to sink and form the bottom and intermediate water implies a large transfer of heat from the ocean to the atmosphere. Understanding the processes involved in the sea ice formation, in the pole ward oceanic transport of the heat from low latitudes and the high latitude heat loss to the atmosphere is an important element for understanding the global heat budget. Eddies in Southern Ocean, around Drake Passage, play an important role on spatial scales ranging from local dynamics to global climate. The aim of present proposal is primarily to use the Topex-Poseidon, ERS and Jason satellite data sets, to verify some of the eddies results found by radiometric and altimeter methods. Although the greater accuracy of the altimeter satellites used should allow a better tracking of eddies in the circumpolar current much farther from the study area, we confine ourselves to Drake Passage, Antarctic Peninsula and the Patagonia shelf, because these would be the range area of our ship Hesperides operation and, consequently, of its radiometer observations . A synoptic set of multidisciplinary observations to establish the status of the polar environment in 2007-2008 These activities may include, between others, the deployment of instrumentation in inaccessible region, collection of satellite data and collection of records of changing polar environments. Our project pretends the display of tide gauges in selected satellite cross over points in the Patagonian Self and Barndsfield sea. That would secure valuable open seas tidal data sets. It could be of interest to remember that the Patagonian shelf regions have tidal ranges among the largest in the word, with amplitudes in M2 reaching more than 4 metres, close to the coast of Argentina. So global and local models have difficulties in modelling the highly nonlinear tides in the region.

What international collaboration is involved in this project?
Monitoring the tidal time series and modelling in the Drake Passage could be recognised of particular importance to the World Ocean Circulation Experiment (WOCE) and the Patagonian shelf. We are a University research group that works in dynamic oceanography using classical methods and satellite altimeters. We have no made contacts with other international groups for present proposal in the understanding that we are open to cooperate with any other group that could be interested in our research proposal mainly if could complement our studies with observations in the Artic.

FIELD ACTIVITY DETAILS

Geographical location(s) for the proposed field activities:
Eddies in Southern Ocean, around Drake Passage, play an important role on spatial scales ranging from local dynamics to global climate. The aim of present proposal is primarily to use the Topex-Poseidon, ERS and Jason satellite data sets, to verify some of the eddies results found by radiometric and altimeter methods. Although the greater accuracy of the altimeter satellites used should allow a better tracking of eddies in the circumpolar current much farther from the study area, we confine ourselves to Drake Passage, Antarctic Peninsula and the Patagonia shelf, because these would be the range area of the Spanish Research Ship Hesperides operation and, consequently, of its radiometer observations

Approximate timeframe(s) for proposed field activities:
Arctic: n/a
Antarctic: (five operative days) between 12/05 – 02/06      (five operative days) between 12/06 – 02/07      (five operative days) between 12/07 – 02/08

Significant facilities will be required for this project:
We will need the support of a ship (Hesperides or Las Palmas) to deploy and recover the open sea tidal gauges in the Patagonian Shelf and Brandsfield sea at the beginning and end of the Antarctic campaigns.(2005-2006, 2006-2007, 2007-2008) During the transects across Drake Passage and its work in other projects in the Arc of Scotia, of the Spanish Research Ship Hesperides we will perform CTD soundings and ADCP transects in the places of possible eddies located by altimeter satellite or radiometer observations. We will record satellite radiometer images on board of Hesperides , in real time, during its work in the Antarctic area. We can share our work with others projects on board.

Will the project leave a legacy of infrastructure?
As was pointed out before the satellite records processing are usually used with the transmission and other corrections supplied by the Agency with the data. Nevertheless these corrections that are applied to the altimetry measurements are global and can present important problems when applied to our study area. Corrections that need to be studied and model in regional bases are: 1-The mismodeling of ocean tides that have a low performance in the polar areas One reason of the modern interest in tides lies in the necessity of being able to compute them, accurately enough to be accurately subtracted out of the altimetry data, both in the open oceans and in the marginal and coastal seas. 2-The propagation velocity of the radio pulses in the troposphere, that present errors at the extreme values, high gradients in altitude close to the surface, and rapid changes of the meteorological parameters in southern polar latitudes. 3-At the frequencies of satellite altimeters the propagation of the radar pulses are slowed down by an amount proportional to the number of free electron contained in the ionosphere. Because its close position of magnetic poles the free electron content varies stronger in the polar zones than in other regions, needing a regional study behaviour correlating the corrections with the magnetic field records in the Antarctic bases. 4-The difference between the mean ocean specula surface, as seen by the altimeter and the mean sea level is the Electromagnetic Bias correction (EMB). Because its definition the EMB will be a function of the significant wave height, other sea states parameters and the radar frequency. Singular sea waves characteristics in the Antarctic Ocean produces a singular behaviour. 5-Doubts remains over the validity in the Southern ocean of the Inverted Barometer static model correction, designed to remove sea level variations from altimeter data caused by variations in the atmospheric pressure. 6-Tidal fluctuations of sea level along the world’s coasts are, in a general sense, quite well known and well measured. However it is only recently that we have been able that became amenable to be measured in the open ocean from space and model them accurately enough in the open oceans for many oceanographic applications In our project we are going to study a local improvement of all these corrections and the models , mainly the local tidal propagation will be of use in future studies of ocean dynamics in the Southern Ocean area. Besides the tidal records in open ocean in Patagonian Self and Brandsfield Sea will be open in the Data Centres.

How is it envisaged that the required logistic support will be secured?
Own national polar operator
National agency
Military support

Has the project been "endorsed" at a national or international level?
: Not yet. After a preliminary acceptance of our proposal by the National Polar Spanish Commitee, it has recommended that the proposal must be endorsed to other more general initiative. After evaluation of our proposal by the IPY we will send it to the Polar National Program of Spain for finance and logistic support.

PROJECT MANAGEMENT AND STRUCTURE

Is the project a short-term expansion (over the IPY 2007-2008 timeframe) of an existing plan, programme or initiative or is it a new autonomous proposal?
New
Our group has already approved and is working out in a Project to study the corrections applied regionally to altimeter records, sea level variability from space observations and ocean dynamic variability in the Atlantic and Mediterranean regions. In this sense our main ideas proposal has already been evaluated positively and supported by the Spanish National Program. The proposal is to extend our North Atlantic studies and results to the Southern Ocean, were the same physical phenomena appears with a higher and singular value.

How will the project be organised and managed?
The Principal Researcher, Dr. Jose J. Alonso, will coordinate our scientific group. Several teams will take the practical part of the Project in the following way: A team of one researcher (Dr. Juan Vidal) and one technician will take the responsibility of the instruments maintenance, calibration and deployment on board, A team of two researchers (Dr. Jose J. Alonso, Manuel Arias) will be in charge of the tide records analysis and constituents propagation and modelling in the Southern Ocean. This work will be an important part of Manuel Arias' PhD Thesis work. A team of three researchers would be on charge of altimetry records analysis and interpretation in the Southern Ocean (Dr. Manuel Catalan, Dra. Pilar Villares and Dr. Jesus Gomez Enri) A team of three researchers would be on charge of radiometer records in Antarctic Campaigns on board of ship, altimeter detection of Eddies, CTD soundings and its interpretation (Dr. Manuel Catalan, Dr. Rafael Jimenez Garay, Dr. Pilar Villares) Dr. Jose J. Alonso will be in charge of Project data management. All group components will take part in the publication of the results

What are the initial plans of the project for addressing the education, outreach and communication issues outlined in the Framework document?
As was pointed out, the project is developed by an university group and the records received from Agency AVISO with the altimeter satellites information, the CTD soundings, the results of the open ocean tide gauges and the mathematical treatment and modelling. Our group is composed, in a great part, by University Professors with large experience in Physical Oceanography, Spatial Oceanography and data management that are responsible for PhD Thesis directions to doctorate students that work in our Departments.

What are the initial plans of the project to address data management issues (as outlined in the Framework document)?
Our data management plan would ensure the data usability for other IPY scientific projects following ‘ The recommendation on data management for the international Polar Year 2007/2008’ as prepared by the Joint Committee on Antarctic Data management’ (JCADM) of SCAR-COMNAP. Following preceding ideas our data management plan would be that the data collected by our group, during the Project will be send, to the National Centre of Polar Data of Spain that would distribute the information according with the IPY data policy to enable the data widely use, providing an standardized data set that can be referenced in future research. .

How is it proposed to fund the project?
f present proposal were approved by the IPY our funds will be: 1-We will perform a Project proposal to our Spanish Polar National Program asking for the necessary economical support and time on ships. 2-Our laboratories in the University will contribute with instruments and infrastructure support to the field work, data gathering and interpretation of the information recorded in the Project.

Is there additional information you wish to provide?
Finally we would like to summarise that our Project has as clear objectives: 1-Improve the altimeter geophysical corrections in a singular geographical place as is the Antarctic oceans and the Patagonian Shelf. 2-Improve regionally the tidal models in the area. 3-Detect eddies crossing the Drake Passage, Scotia Arc, Patagonian Self studying its structure at depth and physical water masses characteristics using old data CTD data (from 1992 on) and CTD new soundings 4-Compute the satellite altimeter series to compute the mean sea level tendencies in Polar Regions. 5-Use the regional corrections in ocean dynamic studies in the area. To do it we will use: 1-Altimeter satellite data received from the French agency AVISO for Topex/Poseidon, ERS, Jason satellites. 2-Perform a display of open sea tide gauges in the satellites cross over points in Patagonian Shelf, Drake Passage and Brandsfield Sea. 3-CTD soundings in possible eddies detected with continuous radiometer observation on board of Hesperides during the Antarctic campaigns. 4-Because the nature of our needs we can use our ship requirements with other programs development on board.

PROPOSER DETAILS

Prof Jose Juan Alonso del Rosario
Poligono del Rio San Pedro, s/n., Puerto Real


11510
Spain

Tel: 956 016054
Mobile: 685873992
Fax: 956016079
Email:

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