Description: King George Island ice cap geometry updated with airborne GPR measurements Earth System Science Data Discussions, 4, 123-139, 2011 Author(s): M. Rückamp and N. Blindow Ice geometry is a mandatory requirement for numerical modelling purposes. In this paper we present a consistent data set for the ice thickness, the bedrock topography and the ice surface topography of the King George Island ice cap (Arctowski Icefield and the adjacent central part). The newly data set is composed of groundbased and airborne Ground Penetrating Radar (GPR) and differential GPS (DGPS) measurements, obtained during several field campaigns. Blindow et al. (2010) already provided a comprehensive overview of the groundbased measurements carried out in the safely accessible area of the ice cap. The updated data set incorporates airborne measurements in the heavily crevassed coastal areas. Therefore, in this paper special attention is paid to the airborne measurements by addressing the used instrument, survey, and data processing in more detail. In particular, the inclusion of airborne GPR measurements with the 30 MHz BGR-P30-System developed at the Institute of Geophysics (University of Münster) completes the picture of the ice geometry substantially. The compiled digital elevation model of the bedrock shows a rough, highly variable topography with pronounced valleys, ridges, and troughs. Mean ice thickness is ~240 m, with a maximum value of ~400 m in the surveyed area. Noticeable are bounded areas in the bedrock topography below sea level where marine based ice exists. The provided data set is required as a basis for future monitoring attempts or as input for numerical modelling experiments. The data set is available from the PANGAEA database at doi:10.1594/PANGAEA.770567 .

Description: Data recovery of A06 and A07 WOCE cruises Earth System Science Data Discussions, 4, 99-122, 2011 Author(s): N. M. Fajar, F. F. Pérez, A. Velo, and A. F. Ríos The WOCE cruises were carried out during the 1990s and were included in GLODAP, which is an easily usable, available and fully calibrated global database. A T and C T data, together with the rest of carbon variables, were subjected to rigorous quality control and some adjustments were done assuming biases, in case of A T and C T , not greater than ±6 μmol kg −1 and ±4 μmol kg −1 , respectively. The A06 and A07 cruises were deleted from GLODAP database owing to A T and C T data were not suitable for analysis. However, these data are still available in CLIVAR and Carbon Hydrographic Data Office web site, demonstrated the unreliable quality of A T and C T , but contrarily, the more realistic profiles of pH data. The main goal of the present work is to recover A T and C T data of A06 and A07 using GLODAP database combining with CARINA database and the most contemporary cruise MOC 2 Equatorial 2010. Thus, A T data of A06 and A07 will be renewed using directly these data in a particular application of Multiple Linear Regression: the 3-D moving window MLR estimation method. Moreover, C T data will be recalculated using the C T A T ratio together with the obtained results from the crossovers analysis method. In order to demonstrate the quality of the recovered A T and C T , the new pH has been calculated, showing the good agreement in terms of pH obtained between A06 and A07 related to MOC 2 . To sum up, the entire carbon databases of A06 and A07 were checked and recovered.

Description: Proglacial river dataset from the Akuliarusiarsuup Kuua River northern tributary, Southwest Greenland, 2008–2010 Earth System Science Data Discussions, 4, 71-97, 2011 Author(s): A. K. Rennermalm, L. C. Smith, V. W. Chu, R. R. Forster, J. E. Box, and B. Hagedorn Pressing scientific questions concerning the Greenland ice sheet's climatic sensitivity, hydrology, and contributions to current and future sea level rise require hydrological datasets to resolve. While direct observations of ice sheet meltwater losses can be obtained in terrestrial rivers draining the ice sheet and from lake levels, few such datasets exist. We present a new dataset of meltwater river discharge for the vicinity of Kangerlussuaq, Southwest Greenland. The dataset contains measurements of river water level and discharge for three sites along the Akuliarusiarsuup Kuua (Watson) River's northern tributary, with 30 min temporal resolution between June 2008 and August 2010. Additional data of water temperature, air pressure, and lake water level and temperature are also provided. Discharge data were measured at sites with near-ideal properties for such data collection. Regardless, high water bedload and turbulent flow introduce considerable uncertainty. These were constrained and quantified using statistical techniques, which revealed that the greatest discharge data uncertainties are associated with streambed elevation change and measurements. Large portions of stream channels deepened according to statistical tests, but poor precision of streambed depth measurements also added uncertainty. Data will periodically be extended, and are available in Open Access at doi:10.1594/PANGAEA.762818 .

Description: Simulation of the time-variable gravity field by means of coupled geophysical models Earth System Science Data Discussions, 4, 27-70, 2011 Author(s): Th. Gruber, J. L. Bamber, M. F. P. Bierkens, H. Dobslaw, M. Murböck, M. Thomas, L. P. H. van Beek, T. van Dam, L. L. A. Vermeersen, and P. N. A. M. Visser Time variable gravity fields, reflecting variations of mass distribution in the system Earth is one of the key parameters to understand the changing Earth. Mass variations are caused either by redistribution of mass in, on or above the Earth's surface or by geophysical processes in the Earth's interior. The first set of observations of monthly variations of the Earth gravity field was provided by the US/German GRACE satellite mission beginning in 2002. This mission is still providing valuable information to the science community. However, as GRACE has outlived its expected lifetime, the geoscience community is currently seeking successor missions in order to maintain the long time series of climate change that was begun by GRACE. Several studies on science requirements and technical feasibility have been conducted in the recent years. These studies required a realistic model of the time variable gravity field in order to perform simulation studies on sensitivity of satellites and their instrumentation. This was the primary reason for the European Space Agency (ESA) to initiate a study on "Monitoring and Modelling individual Sources of Mass Distribution and Transport in the Earth System by Means of Satellites". The goal of this interdisciplinary study was to create as realistic as possible simulated time variable gravity fields based on coupled geophysical models, which could be used in the simulation processes in a controlled environment. For this purpose global atmosphere, ocean, continental hydrology and ice models were used. The coupling was performed by using consistent forcing throughout the models and by including water flow between the different domains of the Earth system. In addition gravity field changes due to solid Earth processes like continuous glacial isostatic adjustment (GIA) and a sudden earthquake with co-seismic and post-seismic signals were modelled. All individual model results were combined and converted to gravity field spherical harmonic series, which is the quantity commonly used to describe the Earth's global gravity field. The result of this study is a twelve-year time-series of 6-hourly time variable gravity field spherical harmonics up to degree and order 180 corresponding to a global spatial resolution of 1 degree in latitude and longitude. In this paper, we outline the input data sets and the process of combining these data sets into a coherent model of temporal gravity field changes. The resulting time series was used in some follow-on studies and is available to anybody interested via a Website.

Description: Observations of the altitude of the volcanic plume during the eruption of Eyjafjallajökull, April–May 2010 Earth System Science Data Discussions, 4, 1-25, 2011 Author(s): P. Arason, G. N. Petersen, and H. Bjornsson The eruption of Eyjafjallajökull volcano in 2010 lasted for 39 days, 14 April–23 May. The eruption had two explosive phases separated by a phase with lava formation and reduced explosive activity. The height of the plume was monitored every 5 min with a C-band weather radar located in Keflavík International Airport, 155 km distance from the volcano. Furthermore, several web cameras were mounted with a view of the volcano, and their images saved every five seconds. Time series of the plume-top altitude were constructed from the radar observations and images from a web camera located in the village Hvolsvöllur at 34 km distance from the volcano. This paper presents the independent radar and web camera time series and performs cross validation. The echo top radar series of the altitude of the volcanic plume are publicly available from the Pangaea Publishing Network ( http://doi.pangaea.de/10.1594/PANGAEA.760690 ).

Description: Assessing the internal consistency of the CARINA data base in the Pacific sector of the Southern Ocean Earth System Science Data Discussions, 2, 555-578, 2009 Author(s): C. L. Sabine, M. Hoppema, R. M. Key, B. Tilbrook, S. van Heuven, C. Lo Monaco, N. Metzl, M. Ishii, A. Murata, and S. Musielewicz The CARINA project is aimed at gathering and providing secondary quality control checks on carbon and carbon-relevant hydrographic and geochemical data from cruises all across the Atlantic, Arctic and Southern Ocean. In total the project gathered 188 cruises that were not previously available to the public. Of these 188 cruises, 37 are part of the Southern Ocean. Parameters from the Southern Ocean cruises, including total carbon dioxide (TCO 2 ), total alkalinity, oxygen, nitrate, phosphate and silicate, were examined for cruise-to-cruise consistency. pH and chlorofluorocarbons (CFCs) are also part of the data base, but are not discussed here. This paper focuses on the quality control of the Southern Ocean data from the Pacific sector which consisted of 29 cruises of which 17 were included in a previous synthesis called GLODAP, 11 were new cruises from the CARINA dataset, and one cruise was included in GLODAP but was updated with new data and therefore also included in CARINA. The Pacific sector quality control procedures included crossover analysis between stations and inversion analysis of all crossover data. The GLODAP data were included into the analysis as reference cruises but without applying the GLODAP recommended adjustments so the corrections could be independently verified. The outcome of this effort is an internally consistent, high-quality carbon data set for all cruises, including the reference cruises.

Description: The CARINA data synthesis project: introduction and overview Earth System Science Data Discussions, 2, 579-624, 2009 Author(s): R. M. Key, T. Tanhua, A. Olsen, M. Hoppema, S. Jutterström, C. Schirnick, S. van Heuven, A. Kozyr, X. Lin, A. Velo, D. W. R. Wallace, and L. Mintrop The original goal of the CARINA (Carbon in Atlantic Ocean) data synthesis project was to create a merged calibrated data set from open ocean subsurface measurements by European scientists that would be generally useful for biogeochemical investigations in the North Atlantic and in particular, studies involving the carbon system. Over time the geographic extent expanded to include the entire Atlantic, the Arctic and the Southern Ocean and the international collaboration broadened significantly. In this paper we give a brief history of the project, a general overview of data included and an outline of the procedures used during the synthesis. The end result of this project was a set of 3 data products, one for each of the listed ocean regions. It is critical that anyone who uses any of the CARINA data products recognize that the data products are not simply concatenations of the originally measured values. Rather, the data have been through an extensive calibration procedure designed to remove measurement bias and bad data. Also a significant fraction of the individual values in the data products were derived either by direct calculation or some means of approximation. These data products were constructed for basin scale biogeochemical investigations and may be inappropriate for investigations involving small areal extent or similar detailed analyses. More information on specific parts of this project can be found in companion articles in this issue. In particular, Tanhua et al. (2009) and Tanhua (2009) describe the procedures and software used to remove measurement bias from the original data. The three data products and a significant volume of supporting information are available from the CARINA web site hosted by the Carbon Dioxide Information Analysis Center (CDIAC: http://cdiac.esd.ornl.gov/oceans/CARINA/Carina_inv.html ). Anyone wanting to use the data is advised to get the highest version number of each data product. Incremental versions represent either corrections or additions. The web site documents specifics of the changes.

Description: Nordic Seas and Arctic Ocean CFC data in CARINA Earth System Science Data Discussions, 2, 493-536, 2009 Author(s): E. Jeansson, K. A. Olsson, T. Tanhua, and J. L. Bullister Water column data of carbon and carbon relevant hydrographic and hydrochemical parameters from 188 previously non-publicly available cruises in the Arctic, Atlantic, and Southern Ocean have been retrieved and merged into a new database: CARINA (CARbon IN the Atlantic). The data have been subject to rigorous quality control (QC) in order to ensure highest possible quality and consistency. The data for most of the parameters included were examined in order to quantify systematic biases in the reported values, i.e. secondary quality control. Significant biases have been corrected for in the data products, i.e. the three merged files with measured, calculated and interpolated values for each of the three CARINA regions; the Arctic Mediterranean Seas (AMS), the Atlantic (ATL) and the Southern Ocean (SO). The Arctic Mediterranean Seas is comprised of the Arctic Ocean and the Nordic Seas, and the quality control was carried out separately in these two areas. Here we present an overview of the QC of the CFC data for the Arctic Mediterranean Seas, including the chlorofluorocarbons CFC-11, CFC-12 and CFC-113, as well as carbon tetrachloride (CCl 4 ). For the secondary QC of the CFCs we used a combination of tools, including the evaluation of depth profiles and CFC ratios, surface saturations and a crossover analysis. This resulted in a multiplicative adjustment of some cruise data, while some other cruises were flagged with questionable quality, which excluded them from the final data product.

Description: Nordic Seas dissolved oxygen data in CARINA Earth System Science Data Discussions, 2, 537-553, 2009 Author(s): E. Falck and A. Olsen Water column data of carbon and carbon relevant hydrographic and hydrochemical parameters from 188 previously non-publicly available cruises in the Arctic, Atlantic, and Southern Ocean have been retrieved and merged into a new database: CARINA (CARbon IN the Atlantic). The data have been subject to rigorous quality control (QC) in order to ensure highest possible quality and consistency. The data for most of the parameters included were examined in order to quantify systematic biases in the reported values, i.e. secondary quality control. Significant biases have been corrected for in the data products, i.e. the three merged files with measured, calculated, and interpolated values for each of the three CARINA regions; the Arctic Mediterranean Seas (AMS), the Atlantic (ATL), and the Southern Ocean (SO). With the adjustments the CARINA database is consistent both internally as well as with GLODAP (Key et al., 2004) and is suitable for accurate assessments of, for example, oceanic carbon inventories and uptake rates and for model validation. The Arctic Mediterranean Seas includes the Arctic Ocean and the Nordic Seas (Greenland, Norwegian, and Iceland Seas), and the quality control was carried out separately in these two areas. This contribution presents an account of the quality control of the dissolved oxygen data from the Nordic Seas in CARINA. Out of the 35 cruises from the Nordic Seas included in CARINA, 32 had oxygen data. The data from 4 of these were found to be biased low and were subject to adjustment. Thus the final CARINA data product contains oxygen data from 32 cruises from the Nordic Seas, and these data appear consistent to ±1% (corresponds to ±3 μmol kg −1 in the deep water).

Description: CARINA data synthesis project: pH data scale unification and cruise adjustments Earth System Science Data Discussions, 2, 421-475, 2009 Author(s): A. Velo, F. F. Pérez, X. Lin, R. M. Key, T. Tanhua, M. de la Paz, S. van Heuven, S. Jutterström, and A. F. Ríos Data on carbon and carbon-relevant hydrographic and hydrochemical parameters from previously non-publicly available cruise data sets in the Artic Mediterranean Seas (AMS), Atlantic and Southern Ocean have been retrieved and merged to a new database: CARINA (CARbon IN the Atlantic). These data have gone through rigorous quality control (QC) procedures to assure the highest possible quality and consistency. The data for most of the measured parameters in the CARINA database were objectively examined in order to quantify systematic differences in the reported values, i.e. secondary quality control. Systematic biases found in the data have been corrected in the data products, i.e. three merged data files with measured, calculated and interpolated data for each of the three CARINA regions; AMS, Atlantic and Southern Ocean. Out of a total of 188 cruise entries in the CARINA database, 59 reported pH measured values. Here we present details of the secondary QC on pH for the CARINA database. Procedures of quality control, including crossover analysis between cruises and inversion analysis of all crossover data are briefly described. Adjustments were applied to the pH values for 21 of the cruises in the CARINA dataset. With these adjustments the CARINA database is consistent both internally as well as with GLODAP data, an oceanographic data set based on the World Hydrographic Program in the 1990s. Based on our analysis we estimate the internal accuracy of the CARINA pH data to be 0.005 pH units. The CARINA data are now suitable for accurate assessments of, for example, oceanic carbon inventories and uptake rates and for model validation.