Description: Surface Ocean CO 2 Atlas (SOCAT) gridded data products Earth System Science Data Discussions, 5, 781-804, 2012 Author(s): C. L. Sabine, S. Hankin, H. Koyuk, D. C. E. Bakker, B. Pfeil, A. Olsen, N. Metzl, A. Kozyr, A. Fassbender, A. Manke, J. Malczyk, J. Akl, S. R. Alin, R. G. J. Bellerby, A. Borges, J. Boutin, P. J. Brown, W.-J. Cai, F. P. Chavez, A. Chen, C. Cosca, R. A. Feely, M. González-Dávila, C. Goyet, N. Hardman-Mountford, C. Heinze, M. Hoppema, C. W. Hunt, D. Hydes, M. Ishii, T. Johannessen, R. M. Key, A. Körtzinger, P. Landschützer, S. K. Lauvset, N. Lefèvre, A. Lenton, A. Lourantou, L. Merlivat, T. Midorikawa, L. Mintrop, C. Miyazaki, A. Murata, A. Nakadate, Y. Nakano, S. Nakaoka, Y. Nojiri, A. M. Omar, X. A. Padin, G.-H. Park, K. Paterson, F. F. Perez, D. Pierrot, A. Poisson, A. F. Ríos, J. Salisbury, J. M. Santana-Casiano, V. V. S. S. Sarma, R. Schlitzer, B. Schneider, U. Schuster, R. Sieger, I. Skjelvan, T. Steinhoff, T. Suzuki, T. Takahashi, K. Tedesco, M. Telszewski, H. Thomas, B. Tilbrook, D. Vandemark, T. Veness, A. J. Watson, R. Weiss, C. S. Wong, and H. Yoshikawa-Inoue A well documented, publicly available, global data set for surface ocean carbon dioxide (CO 2 ) parameters has been called for by international groups for nearly two decades. The Surface Ocean CO 2 Atlas (SOCAT) project was initiated by the international marine carbon science community in 2007 with the aim of providing a comprehensive, publicly available, regularly updated, global data set of marine surface CO 2 , which had been subject to quality control (QC). SOCAT version 1.5 was made public in September 2011 and holds 6.3 million quality controlled surface CO 2 data from the global oceans and coastal seas, spanning four decades (1968–2007). The SOCAT gridded data is the second data product to come from the SOCAT project. Recognizing that some groups may have trouble working with millions of measurements, the SOCAT gridded product was generated to provide a robust regularly spaced f CO 2 product with minimal spatial and temporal interpolation which should be easier to work with for many applications. Gridded SOCAT is rich with information that has not been fully explored yet, but also contains biases and limitations that the user needs to recognize and address.

Description: A uniform, quality controlled Surface Ocean CO 2 Atlas (SOCAT) Earth System Science Data Discussions, 5, 735-780, 2012 Author(s): B. Pfeil, A. Olsen, D. C. E. Bakker, S. Hankin, H. Koyuk, A. Kozyr, J. Malczyk, A. Manke, N. Metzl, C. L. Sabine, J. Akl, S. R. Alin, R. G. J. Bellerby, A. Borges, J. Boutin, P. J. Brown, W.-J. Cai, F. P. Chavez, A. Chen, C. Cosca, A. J. Fassbender, R. A. Feely, M. González-Dávila, C. Goyet, N. Hardman-Mountford, C. Heinze, M. Hood, M. Hoppema, C. W. Hunt, D. Hydes, M. Ishii, T. Johannessen, S. D. Jones, R. M. Key, A. Körtzinger, P. Landschützer, S. K. Lauvset, N. Lefèvre, A. Lenton, A. Lourantou, L. Merlivat, T. Midorikawa, L. Mintrop, C. Miyazaki, A. Murata, A. Nakadate, Y. Nakano, S. Nakaoka, Y. Nojiri, A. M. Omar, X. A. Padin, G.-H. Park, K. Paterson, F. F. Perez, D. Pierrot, A. Poisson, A. F. Ríos, J. M. Santana-Casiano, J. Salisbury, V. V. S. S. Sarma, R. Schlitzer, B. Schneider, U. Schuster, R. Sieger, I. Skjelvan, T. Steinhoff, T. Suzuki, T. Takahashi, K. Tedesco, M. Telszewski, H. Thomas, B. Tilbrook, J. Tjiputra, D. Vandemark, T. Veness, R. Wanninkhof, A. J. Watson, R. Weiss, C. S. Wong, and H. Yoshikawa-Inoue A well documented, publicly available, global data set of surface ocean carbon dioxide (CO 2 ) parameters has been called for by international groups for nearly two decades. The Surface Ocean CO 2 Atlas (SOCAT) project was initiated by the international marine carbon science community in 2007 with the aim of providing a comprehensive, publicly available, regularly updated, global data set of marine surface CO 2 , which had been subject to quality control (QC). Many additional CO 2 data, not yet made public via the Carbon Dioxide Information Analysis Center (CDIAC), were retrieved from data originators, public websites and other data centres. All data were put in a uniform format following a strict protocol. Quality control was carried out according to clearly defined criteria. Regional specialists performed the quality control, using state-of-the-art web-based tools, specially developed for accomplishing this global team effort. SOCAT version 1.5 was made public in September 2011 and holds 6.3 million quality controlled surface CO 2 data points from the global oceans and coastal seas, spanning four decades (1968–2007). Three types of data products are available: individual cruise files, a merged complete data set and gridded products. With the rapid expansion of marine CO 2 data collection and the importance of quantifying net global oceanic CO 2 uptake and its changes, sustained data synthesis and data access are priorities.

Description: Database of diazotrophs in global ocean: abundances, biomass and nitrogen fixation rates Earth System Science Data Discussions, 5, 47-106, 2012 Author(s): Y.-W. Luo, S. C. Doney, L. A. Anderson, M. Benavides, A. Bode, S. Bonnet, K. H. Boström, D. Böttjer, D. G. Capone, E. J. Carpenter, Y. L. Chen, M. J. Church, J. E. Dore, L. I. Falcón, A. Fernández, R. A. Foster, K. Furuya, F. Gómez, K. Gundersen, A. M. Hynes, D. M. Karl, S. Kitajima, R. J. Langlois, J. LaRoche, R. M. Letelier, E. Marañón, D. J. McGillicuddy Jr., P. H. Moisander, C. M. Moore, B. Mouriño-Carballido, M. R. Mulholland, J. A. Needoba, K. M. Orcutt, A. J. Poulton, P. Raimbault, A. P. Rees, L. Riemann, T. Shiozaki, A. Subramaniam, T. Tyrrell, K. A. Turk-Kubo, M. Varela, T. A. Villareal, E. A. Webb, A. E. White, J. Wu, and J. P. Zehr Marine N 2 fixing microorganisms, termed diazotrophs, are a key functional group in marine pelagic ecosystems. The biological fixation of dinitrogen (N 2 ) to bioavailable nitrogen provides an important new source of nitrogen for pelagic marine ecosystems and influences primary productivity and organic matter export to the deep ocean. As one of a series of efforts to collect biomass and rates specific to different phytoplankton functional groups, we have constructed a database on diazotrophic organisms in the global pelagic upper ocean by compiling about 12 000 direct field measurements of cyanobacterial diazotroph abundances (based on microscopic cell counts or qPCR assays targeting the nifH genes) and N 2 fixation rates. Biomass conversion factors are estimated based on cell sizes to convert abundance data to diazotrophic biomass. The database is limited spatially, lacking large regions of the ocean especially in the Indian Ocean. The data are approximately log-normal distributed, and large variances exist in most sub-databases with non-zero values differing 5 to 8 orders of magnitude. Lower mean N 2 fixation rate was found in the North Atlantic Ocean than the Pacific Ocean. Reporting the geometric mean and the range of one geometric standard error below and above the geometric mean, the pelagic N 2 fixation rate in the global ocean is estimated to be 62 (53–73) Tg N yr −1 and the pelagic diazotrophic biomass in the global ocean is estimated to be 4.7 (2.3–9.6) Tg C from cell counts and to 89 (40–200) Tg C from nifH -based abundances. Uncertainties related to biomass conversion factors can change the estimate of geometric mean pelagic diazotrophic biomass in the global ocean by about ±70%. This evolving database can be used to study spatial and temporal distributions and variations of marine N 2 fixation, to validate geochemical estimates and to parameterize and validate biogeochemical models. The database is stored in PANGAEA ( http://doi.pangaea.de/10.1594/PANGAEA.774851 ).

Description: Technical details concerning development of a 1200-yr proxy index for global volcanism Earth System Science Data Discussions, 5, 1-28, 2012 Author(s): T. J. Crowley and M. B. Unterman This technical report describes details of developing a volcano forcing reconstruction (Crowley et al., 2008) for climate models that is based primarily on sulphate records in Antarctic and Greenland ice cores. The chronology of eruptions is considered accurate to within 1 yr for the interval AD 1104–2000 and 2 yr for AD 800–1103. The reconstruction involves: (1) calibration against satellite aerosol optical depth (AOD) estimates of the 1991 Pinatubo/Hudson eruptions; (2) partial validation against independent lunar estimates of AOD and global sulphate emissions; (3) partial assessment of uncertainties in AOD estimates; (4) assessment of possible tropical "false positives" in ice core reconstructions due to simultaneous occurrence of mid/high-latitude eruptions in each hemisphere; (5) identification of a new category of eruptions, termed "unipolar" tropical eruptions, in which the eruption plume penetrates mainly to polar regions in only the hemisphere of its eruption; (6) use of different growth curves for high- and low-latitude eruptions; (7) specification of 2/3 power shortwave scaling for eruptions larger than the 1991 Pinatubo eruption; and (8) compensatory introduction of an estimate of effective particle size that affects lifetime and scattering properties of stratospheric aerosols.

Description: The MPI-Mainz UV/VIS Spectral Atlas of Gaseous Molecules of Atmospheric Interest Earth System Science Data Discussions, 6, 411-433, 2013 Author(s): H. Keller-Rudek, G. K. Moortgat, R. Sander, and R. Sörensen We present the MPI-Mainz UV/VIS Spectral Atlas, which is a large collection of absorption cross sections and quantum yields in the ultraviolet and visible (UV/VIS) wavelength region for gaseous molecules and radicals primarily of atmospheric interest. The data files contain results of individual measurements, covering research of almost a whole century. To compare and visualize the data sets, multicoloured graphical representations have been created. The Spectral Atlas is available on the internet at http://www.uv-vis-spectral-atlas-mainz.org . It now appears with improved browse and search options, based on new database software. In addition to the web pages, which are continuously updated, a frozen version of the data is available under the doi:10.5281/zenodo.6951 .

Description: Use of various remote sensing land cover products for PFT mapping over Siberia Earth System Science Data Discussions, 6, 255-296, 2013 Author(s): C. Ottlé, J. Lescure, F. Maignan, B. Poulter, T. Wang, and N. Delbart High-latitude ecosystems play an important role in the global carbon cycle and in regulating the climate system and are presently undergoing rapid environmental change. Accurate land cover datasets are required to both document these changes as well as to provide land-surface information for benchmarking and initializing earth system models. Earth system models also require specific land cover classification systems based on plant functional types, rather than species or ecosystems, and so post-processing of existing land cover data is often required. This study compares over Siberia, multiple land cover datasets against one another and with auxiliary data to identify key uncertainties that contribute to variability in Plant Functional Type (PFT) classifications that would introduce errors in earth system modeling. Land cover classification systems from GLC 2000, GlobCover 2005 and 2009, and MODIS collections 5 and 5.1 are first aggregated to a common legend, and then compared to high-resolution land cover classification systems, continuous vegetation fields (MODIS-VCF) and satellite-derived tree heights (to discriminate against sparse, shrub, and forest vegetation). The GlobCover dataset, with a lower threshold for tree cover and taller tree heights and a better spatial resolution, tends to have better distributions of tree cover compared to high-resolution data. It has therefore been chosen to build new PFTs maps for the ORCHIDEE land surface model at 1 km scale. Compared to the original PFT dataset, the new PFT maps based on GlobCover 2005 and an updated cross-walking approach mainly differ in the characterization of forests and degree of tree cover. The partition of grasslands and bare soils now appears more realistic compared with ground-truth data. This new vegetation map provides a framework for further development of new PFTs in the ORCHIDEE model like shrubs, lichens and mosses, to better represent the water and carbon cycles in northern latitudes. Updated land cover datasets are critical for improving and maintaining the relevance of earth system models for assessing climate and human impacts on biogeochemistry and biophysics. The new PFT map at 5 km scale is available for download from the PANGAEA website, at: doi:10.1594/PANGAEA.810709 .

Description: A long-term and reproducible passive microwave sea ice concentration data record for climate studies and monitoring Earth System Science Data Discussions, 6, 95-117, 2013 Author(s): G. Peng, W. N. Meier, D. J. Scott, and M. H. Savoie A long-term, consistent, and reproducible satellite-based passive microwave sea ice concentration climate data record (CDR) is available for climate studies, monitoring, and model validation with an initial operation capability (IOC). The daily and monthly sea ice concentration data are on the National Snow and Ice Data Center (NSIDC) polar stereographic grid with nominal 25 × 25 km grid cells in both the Southern and Northern Hemisphere Polar Regions from 9 July 1987 to 31 December 2007 with an update through 2011 underway. The data files are available in the NetCDF data format at http://nsidc.org/data/g02202.html and archived by the National Oceanic and Atmospheric Administration (NOAA)'s National Climatic Data Center (NCDC) under the satellite climate data record program ( http://www.ncdc.noaa.gov/cdr/operationalcdrs.html ). The description and basic characteristics of the NOAA/NSIDC passive microwave sea ice concentration CDR are presented here. The CDR provides similar spatial and temporal variability as the heritage products to the user communities with the additional documentation, traceability, and reproducibility that meet current standards and guidelines for climate data records. The dataset along with detailed data processing steps and error source information can be found at: doi:10.7265/N5B56GN3 .

Description: A spatial database of wildfires in the United States, 1992–2011 Earth System Science Data Discussions, 6, 297-366, 2013 Author(s): K. C. Short The statistical analysis of wildfire activity is a critical component of national wildfire planning, operations, and research in the United States (US). However, there are multiple federal, state, and local entities with wildfire protection and reporting responsibilities in the US, and no single, unified system of wildfire record-keeping exists. To conduct even the most rudimentary interagency analyses of wildfire numbers and area burned from the authoritative systems of record, one must harvest records from dozens of disparate databases with inconsistent information content. The onus is then on the user to check for and purge redundant records of the same fire (i.e. multijurisdictional incidents with responses reported by several agencies or departments) after pooling data from different sources. Here we describe our efforts to acquire, standardize, error-check, compile, scrub, and evaluate the completeness of US federal, state, and local wildfire records from 1992–2011 for the national, interagency Fire Program Analysis (FPA) application. The resulting FPA Fire-occurrence Database (FPA FOD) includes nearly 1.6 million records from the 20 yr period, with values for at least the following core data elements: location at least as precise as a Public Land Survey System section (2.6 km 2 grid), discovery date, and final fire size. The FPA FOD is publicly available from the Research Data Archive of the US Department of Agriculture, Forest Service ( doi:10.2737/RDS-2013-0009 ). While necessarily incomplete in some aspects, the database is intended to facilitate fairly high-resolution geospatial analysis of US wildfire activity over the past two decades, based on available information from the authoritative systems of record.

Description: Juneau Icefield Mass Balance Program 1946–2011 Earth System Science Data Discussions, 6, 119-151, 2013 Author(s): M. Pelto, J. Kavanaugh, and C. McNeil The mass balance records of the Lemon Creek Glacier and Taku Glacier observed by the Juneau Icefield Research Program are the longest continuous glacier mass balance data sets in North America. On Taku Glacier annual mass balance averaged +0.40 m a −1 from 1946–1985 and −0.08 m a −1 from 1986–2011. The recent mass balance decline has resulted in the cessation of the long term thickening of the glacier. Mean annual mass balance on Lemon Creek Glacier has declined from −0.30 m a −1 for the 1953–1985 period to −0.60 m a −1 during the 1986–2011 period. The overall mass balance change is −26.6 m water equivalent, a 29 m of ice thinning over the 55 yr. Probing transects above the transient snow line (TSL) indicate a consistent balance gradient from year to year. Observations of the rate of summer TSL rise on Lemon Creek and Taku Glacier indicate a comparatively consistent rate of 3.8 to 4.1 m d −1 . The relationship between TSL on Lemon Creek and Taku Glacier to other Juneau Icefield glaciers, Norris, Mendenhall, Herbert, and Eagle, is strong with correlations exceeding 0.82 in all cases. doi:10.5065/D6NZ85N3

Description: Short communication: a new dataset for estimating organic carbon storage to 3 m depth in soils of the northern circumpolar permafrost region Earth System Science Data Discussions, 6, 73-93, 2013 Author(s): G. Hugelius, C. Tarnocai, J. G. Bockheim, P. Camill, B. Elberling, G. Grosse, J. W. Harden, K. Johnson, T. Jorgenson, C. D. Koven, P. Kuhry, G. Michaelson, U. Mishra, J. Palmtag, C.-L. Ping, J. O'Donnell, L. Schirrmeister, E. A. G. Schuur, Y. Sheng, L. C. Smith, J. Strauss, and Z. Yu High latitude terrestrial ecosystems are key components in the global carbon (C) cycle. The Northern Circumpolar Soil Carbon Database (NCSCD) was developed to quantify stocks of soil organic carbon (SOC) in the northern circumpolar permafrost region (18.7 × 10 6 km 2 ). The NCSCD is a digital Geographical Information systems (GIS) database compiled from harmonized regional soil classification maps, in which data on soil coverage has been linked to pedon data from the northern permafrost regions. Previously, the NCSCD has been used to calculate SOC content (SOCC) and mass (SOCM) to the reference depths 0–30 cm and 0–100 cm (based on 1778 pedons). It has been shown that soils of the northern circumpolar permafrost region also contain significant quantities of SOC in the 100–300 cm depth range, but there has been no circumpolar compilation of pedon data to quantify this SOC pool and there are no spatially distributed estimates of SOC storage below 100 cm depth in this region. Here we describe the synthesis of an updated pedon dataset for SOCC in deep soils of the northern circumpolar permafrost regions, with separate datasets for the 100–200 cm (524 pedons) and 200–300 cm (356 pedons) depth ranges. These pedons have been grouped into the American and Eurasian sectors and the mean SOCC for different soil taxa (subdivided into Histels, Turbels, Orthels, Histosols, and permafrost-free mineral soil taxa) has been added to the updated NCSCDv2. The updated version of the database is freely available online in several different file formats and spatial resolutions that enable spatially explicit usage in e.g. GIS and/or terrestrial ecosystem models. The potential applications and limitations of the NCSCDv2 in spatial analyses are briefly discussed. An open access data-portal for all the described GIS-datasets is available online at: http://dev1.geo.su.se/bbcc/dev/v3/ncscd/download.php . The NCSCDv2 database has the doi:10.5879/ECDS/00000002 .