Description: A compilation of tropospheric measurements of gas-phase and aerosol chemistry in polar regions Earth System Science Data, 4, 215-282, 2012 Author(s): R. Sander and J. Bottenheim Measurements of atmospheric chemistry in polar regions have been made for more than half a century. Probably the first Antarctic ozone data were recorded in 1958 during the International Geophysical Year. Since then, many measurement campaigns followed, and the results are now spread over many publications in several journals. Here, we have compiled measurements of tropospheric gas-phase and aerosol chemistry made in the Arctic and the Antarctic. It is hoped that this data collection is worth more than the sum of its components and serves as a basis for future analyses of spatial and temporal trends in polar atmospheric chemistry.

Description: Homogenization of Portuguese long-term temperature data series: Lisbon, Coimbra and Porto Earth System Science Data, 4, 187-213, 2012 Author(s): A. L. Morozova and M. A. Valente Three long-term temperature data series measured in Portugal were studied to detect and correct non-climatic homogeneity breaks and are now available for future studies of climate variability. Series of monthly minimum ( T min ) and maximum ( T max ) temperatures measured in the three Portuguese meteorological stations of Lisbon (from 1856 to 2008), Coimbra (from 1865 to 2005) and Porto (from 1888 to 2001) were studied to detect and correct non-climatic breaks. These series, together with monthly series of average temperature ( T aver ) and temperature range (DTR) derived from them, were tested in order to detect breaks, using firstly metadata, secondly a visual analysis, and thirdly four widely used homogeneity tests: von Neumann ratio test, Buishand test, standard normal homogeneity test, and Pettitt test. The homogeneity tests were used in absolute (using temperature series themselves) and relative (using sea-surface temperature anomalies series obtained from HadISST2.0.0.0 close to the Portuguese coast or already corrected temperature series as reference series) modes. We considered the T min , T max and DTR series as most informative for the detection of breaks due to the fact that T min and T max could respond differently to changes in position of a thermometer or other changes in the instrument's environment; T aver series have been used mainly as control. The homogeneity tests showed strong inhomogeneity of the original data series, which could have both internal climatic and non-climatic origins. Breaks that were identified by the last three mentioned homogeneity tests were compared with available metadata containing data such as instrument changes, changes in station location and environment, observation procedures, etc. Significant breaks (significance 95% or more) that coincided with known dates of instrumental changes were corrected using standard procedures. It was also noted that some significant breaks, which could not be connected to known dates of any changes in the park of instruments or stations location and environment, were probably caused by large volcanic eruptions. The corrected series were again tested for homogeneity; the corrected series were considered free of non-climatic breaks when the tests of most of monthly series showed no significant (significance 95% or more) breaks that coincide with dates of known instrument changes. Corrected series are now available within the framework of ERA-CLIM FP7 project for future studies of climate variability ( doi:10.1594/PANGAEA.785377 ).

Description: The global distribution of pteropods and their contribution to carbonate and carbon biomass in the modern ocean Earth System Science Data, 4, 167-186, 2012 Author(s): N. Bednaršek, J. Možina, M. Vogt, C. O'Brien, and G. A. Tarling Pteropods are a group of holoplanktonic gastropods for which global biomass distribution patterns remain poorly described. The aim of this study was to collect and synthesise existing pteropod (Gymnosomata, Thecosomata and Pseudothecosomata) abundance and biomass data, in order to evaluate the global distribution of pteropod carbon biomass, with a particular emphasis on temporal and spatial patterns. We collected 25 939 data points from several online databases and 41 scientific articles. These data points corresponded to observations from 15 134 stations, where 93% of observations were of shelled pteropods (Thecosomata) and 7% of non-shelled pteropods (Gymnosomata). The biomass data has been gridded onto a 360 × 180° grid, with a vertical resolution of 33 depth levels. Both the raw data file and the gridded data in NetCDF format can be downloaded from PANGAEA, doi:10.1594/PANGAEA.777387 . Data were collected between 1950–2010, with sampling depths ranging from 0–2000 m. Pteropod biomass data was either extracted directly or derived through converting abundance to biomass with pteropod-specific length to carbon biomass conversion algorithms. In the Northern Hemisphere (NH), the data were distributed quite evenly throughout the year, whereas sampling in the Southern Hemisphere (SH) was biased towards winter and summer values. 86% of all biomass values were located in the NH, most (37%) within the latitudinal band of 30–60° N. The range of global biomass values spanned over four orders of magnitude, with mean and median (non-zero) biomass values of 4.6 mg C m −3 (SD = 62.5) and 0.015 mg C m −3 , respectively. The highest mean biomass was located in the SH within the 70–80° S latitudinal band (39.71 mg C m −3 , SD = 93.00), while the highest median biomass was in the NH, between 40–50° S (0.06 mg C m −3 , SD = 79.94). Shelled pteropods constituted a mean global carbonate biomass of 23.17 mg CaCO 3 m −3 (based on non-zero records). Total biomass values were lowest in the equatorial regions and equally high at both poles. Pteropods were found at least to depths of 1000 m, with the highest biomass values located in the surface layer (0–10 m) and gradually decreasing with depth, with values in excess of 100 mg C m −3 only found above 200 m depth. Tropical species tended to concentrate at greater depths than temperate or high-latitude species. Global biomass levels in the NH were relatively invariant over the seasonal cycle, but more seasonally variable in the SH. The collected database provides a valuable tool for modellers for the study of marine ecosystem processes and global biogeochemical cycles. By extrapolating regional biomass to a global scale, we established global pteropod biomass to add up to 500 Tg C.

Description: A global diatom database – abundance, biovolume and biomass in the world ocean Earth System Science Data, 4, 149-165, 2012 Author(s): K. Leblanc, J. Arístegui, L. Armand, P. Assmy, B. Beker, A. Bode, E. Breton, V. Cornet, J. Gibson, M.-P. Gosselin, E. Kopczynska, H. Marshall, J. Peloquin, S. Piontkovski, A. J. Poulton, B. Quéguiner, R. Schiebel, R. Shipe, J. Stefels, M. A. van Leeuwe, M. Varela, C. Widdicombe, and M. Yallop Phytoplankton identification and abundance data are now commonly feeding plankton distribution databases worldwide. This study is a first attempt to compile the largest possible body of data available from different databases as well as from individual published or unpublished datasets regarding diatom distribution in the world ocean. The data obtained originate from time series studies as well as spatial studies. This effort is supported by the Marine Ecosystem Model Inter-Comparison Project (MAREMIP), which aims at building consistent datasets for the main plankton functional types (PFTs) in order to help validate biogeochemical ocean models by using carbon (C) biomass derived from abundance data. In this study we collected over 293 000 individual geo-referenced data points with diatom abundances from bottle and net sampling. Sampling site distribution was not homogeneous, with 58% of data in the Atlantic, 20% in the Arctic, 12% in the Pacific, 8% in the Indian and 1% in the Southern Ocean. A total of 136 different genera and 607 different species were identified after spell checking and name correction. Only a small fraction of these data were also documented for biovolumes and an even smaller fraction was converted to C biomass. As it is virtually impossible to reconstruct everyone's method for biovolume calculation, which is usually not indicated in the datasets, we decided to undertake the effort to document, for every distinct species, the minimum and maximum cell dimensions, and to convert all the available abundance data into biovolumes and C biomass using a single standardized method. Statistical correction of the database was also adopted to exclude potential outliers and suspicious data points. The final database contains 90 648 data points with converted C biomass. Diatom C biomass calculated from cell sizes spans over eight orders of magnitude. The mean diatom biomass for individual locations, dates and depths is 141.19 μg C l −1 , while the median value is 11.16 μg C l −1 . Regarding biomass distribution, 19% of data are in the range 0–1 μg C l −1 , 29% in the range 1–10 μg C l −1 , 31% in the range 10–100 μg C l −1 , 18% in the range 100–1000 μg C l −1 , and only 3% 〉 1000 μg C l −1 . Interestingly, less than 50 species contributed to 〉 90% of global biomass, among which centric species were dominant. Thus, placing significant efforts on cell size measurements, process studies and C quota calculations of these species should considerably improve biomass estimates in the upcoming years. A first-order estimate of the diatom biomass for the global ocean ranges from 444 to 582 Tg C, which converts to 3 to 4 Tmol Si and to an average Si biomass turnover rate of 0.15 to 0.19 d −1 . Link to the dataset: doi:10.1594/PANGAEA.777384 .

Description: Future Flows Climate: an ensemble of 1-km climate change projections for hydrological application in Great Britain Earth System Science Data, 4, 143-148, 2012 Author(s): C. Prudhomme, S. Dadson, D. Morris, J. Williamson, G. Goodsell, S. Crooks, L. Boelee, H. Davies, G. Buys, T. Lafon, and G. Watts The dataset Future Flows Climate was developed as part of the project ''Future Flows and Groundwater Levels'' to provide a consistent set of climate change projections for the whole of Great Britain at both space and time resolutions appropriate for hydrological applications, and to enable climate change uncertainty and climate variability to be accounted for in the assessment of their possible impacts on the environment. Future Flows Climate is derived from the Hadley Centre's ensemble projection HadRM3-PPE that is part of the basis of UKCP09 and includes projections in available precipitation (water available to hydrological processes after snow and ice storages have been accounted for) and potential evapotranspiration. It corresponds to an 11-member ensemble of transient projections from January 1950 to December 2098, each a single realisation from a different variant of HadRM3. Data are provided on a 1-km grid over the HadRM3 land areas at a daily (available precipitation) and monthly (PE) time step as netCDF files. Because systematic biases in temperature and precipitation were found between HadRM3-PPE and gridded temperature and precipitation observations for the 1962–1991 period, a monthly bias correction procedure was undertaken, based on a linear correction for temperature and a quantile-mapping correction (using the gamma distribution) for precipitation followed by a spatial downscaling. Available precipitation was derived from the bias-corrected precipitation and temperature time series using a simple elevation-dependant snow-melt model. Potential evapotranspiration time series were calculated for each month using the FAO-56 Penman-Monteith equations and bias-corrected temperature, cloud cover, relative humidity and wind speed from HadRM3-PPE along with latitude of the grid and the day of the year. Future Flows Climate is freely available for non-commercial use under certain licensing conditions. It is the dataset used to generate Future Flows Hydrology, an ensemble of transient projections of daily river flow and monthly groundwater time series for representative river basins and boreholes in Great Britain. doi:10.5285/bad1514f-119e-44a4-8e1e-442735bb9797 .

Description: Two weather radar time series of the altitude of the volcanic plume during the May 2011 eruption of Grímsvötn, Iceland Earth System Science Data, 4, 121-127, 2012 Author(s): G. N. Petersen, H. Bjornsson, P. Arason, and S. von Löwis The eruption of Grímsvötn volcano in Iceland in 2011 lasted for a week, 21–28 May. The eruption was explosive and peaked during the first hours, with the eruption plume reaching 20–25 km altitude. The height of the plume was monitored every 5 min with a C-band weather radar located at Keflavík International Airport and a mobile X-band radar, 257 km and 75 km distance from the volcano respectively. In addition, photographs taken during the first half-hour of the eruption give information regarding the initial rise. Time series of the plume-top altitude were constructed from the radar observations. This paper presents the two independent radar time series. The series have been cross validated and there is a good agreement between them. The echo top radar series of the altitude of the volcanic plume are publicly available from the Pangaea Data Publisher ( doi:10.1594/PANGAEA.778390 ).

Description: A new 100-m Digital Elevation Model of the Antarctic Peninsula derived from ASTER Global DEM: methods and accuracy assessment Earth System Science Data, 4, 129-142, 2012 Author(s): A. J. Cook, T. Murray, A. Luckman, D. G. Vaughan, and N. E. Barrand A high resolution surface topography Digital Elevation Model (DEM) is required to underpin studies of the complex glacier system on the Antarctic Peninsula. A complete DEM with better than 200 m pixel size and high positional and vertical accuracy would enable mapping of all significant glacial basins and provide a dataset for glacier morphology analyses. No currently available DEM meets these specifications. We present a new 100-m DEM of the Antarctic Peninsula (63–70° S), based on ASTER Global Digital Elevation Model (GDEM) data. The raw GDEM products are of high-quality on the rugged terrain and coastal-regions of the Antarctic Peninsula and have good geospatial accuracy, but they also contain large errors on ice-covered terrain and we seek to minimise these artefacts. Conventional data correction techniques do not work so we have developed a method that significantly improves the dataset, smoothing the erroneous regions and hence creating a DEM with a pixel size of 100 m that will be suitable for many glaciological applications. We evaluate the new DEM using ICESat-derived elevations, and perform horizontal and vertical accuracy assessments based on GPS positions, SPOT-5 DEMs and the Landsat Image Mosaic of Antarctica (LIMA) imagery. The new DEM has a mean elevation difference of −4 m (± 25 m RMSE) from ICESat (compared to −13 m mean and ±97 m RMSE for the original ASTER GDEM), and a horizontal error of less than 2 pixels, although elevation accuracies are lower on mountain peaks and steep-sided slopes. The correction method significantly reduces errors on low relief slopes and therefore the DEM can be regarded as suitable for topographical studies such as measuring the geometry and ice flow properties of glaciers on the Antarctic Peninsula. The DEM is available for download from the NSIDC website: http://nsidc.org/data/nsidc-0516.html ( doi:10.5060/D47P8W9D ).

Description: Global marine plankton functional type biomass distributions: Phaeocystis spp. Earth System Science Data, 4, 107-120, 2012 Author(s): M. Vogt, C. O'Brien, J. Peloquin, V. Schoemann, E. Breton, M. Estrada, J. Gibson, D. Karentz, M. A. Van Leeuwe, J. Stefels, C. Widdicombe, and L. Peperzak The planktonic haptophyte Phaeocystis has been suggested to play a fundamental role in the global biogeochemical cycling of carbon and sulphur, but little is known about its global biomass distribution. We have collected global microscopy data of the genus Phaeocystis and converted abundance data to carbon biomass using species-specific carbon conversion factors. Microscopic counts of single-celled and colonial Phaeocystis were obtained both through the mining of online databases and by accepting direct submissions (both published and unpublished) from Phaeocystis specialists. We recorded abundance data from a total of 1595 depth-resolved stations sampled between 1955–2009. The quality-controlled dataset includes 5057 counts of individual Phaeocystis cells resolved to species level and information regarding life-stages from 3526 samples. 83% of stations were located in the Northern Hemisphere while 17% were located in the Southern Hemisphere. Most data were located in the latitude range of 50–70° N. While the seasonal distribution of Northern Hemisphere data was well-balanced, Southern Hemisphere data was biased towards summer months. Mean species- and form-specific cell diameters were determined from previously published studies. Cell diameters were used to calculate the cellular biovolume of Phaeocystis cells, assuming spherical geometry. Cell biomass was calculated using a carbon conversion factor for prymnesiophytes. For colonies, the number of cells per colony was derived from the colony volume. Cell numbers were then converted to carbon concentrations. An estimation of colonial mucus carbon was included a posteriori, assuming a mean colony size for each species. Carbon content per cell ranged from 9 pg C cell −1 (single-celled Phaeocystis antarctica ) to 29 pg C cell −1 (colonial Phaeocystis globosa ). Non-zero Phaeocystis cell biomasses (without mucus carbon) range from 2.9 × 10 −5 to 5.4 × 10 3 μg C l −1 , with a mean of 45.7 μg C l −1 and a median of 3.0 μg C l −1 . The highest biomasses occur in the Southern Ocean below 70° S (up to 783.9 μg C l −1 ) and in the North Atlantic around 50° N (up to 5.4 × 10 3 μg C l −1 ). The original and gridded data can be downloaded from PANGAEA, doi:10.1594/PANGAEA.779101 .

Description: Picoheterotroph ( Bacteria and Archaea ) biomass distribution in the global ocean Earth System Science Data, 4, 101-106, 2012 Author(s): E. T. Buitenhuis, W. K. W. Li, M. W. Lomas, D. M. Karl, M. R. Landry, and S. Jacquet We compiled a database of 39 766 data points consisting of flow cytometric and microscopical measurements of picoheterotroph abundance, including both Bacteria and Archaea . After gridding with 1° spacing, the database covers 1.3% of the ocean surface. There are data covering all ocean basins and depths except the Southern Hemisphere below 350 m or from April until June. The average picoheterotroph biomass is 3.9 ± 3.6 μg C l −1 with a 20-fold decrease between the surface and the deep sea. We estimate a total ocean inventory of about 1.3 × 10 29 picoheterotroph cells. Surprisingly, the abundance in the coastal regions is the same as at the same depths in the open ocean. Using an average of published open ocean measurements for the conversion from abundance to carbon biomass of 9.1 fg cell −1 , we calculate a picoheterotroph carbon inventory of about 1.2 Pg C. The main source of uncertainty in this inventory is the conversion factor from abundance to biomass. Picoheterotroph biomass is ~2 times higher in the tropics than in the polar oceans. doi:10.1594/PANGAEA.779142

Description: Dobson, Brewer, ERA-40 and ERA-Interim original and merged total ozone data sets – evaluation of differences: a case study, Hradec Králové (Czech), 1961–2010 Earth System Science Data, 4, 91-100, 2012 Author(s): K. Vaníček, L. Metelka, P. Skřivánková, and M. Staněk Homogenized data series of total ozone measurements taken by the regularly and well calibrated Dobson and Brewer spectrophotometers at Hradec Králové (Czech) and the data from the re-analyses ERA-40 and ERA-Interim were merged and compared to investigate differences between the particular data sets originated in Central Europe, the Northern Hemisphere (NH) mid-latitudes. The Dobson-to-Brewer transfer function and the algorithm for approximation of the data from the re-analyses were developed, tested and applied for creation of instrumentally consistent and completed total ozone data series of the 50-yr period 1961–2010 of observations. This correction has reduced the well-known seasonal differences between Dobson and Brewer data below the 1% calibration limit of the spectrophotometers. Incorporation of the ERA-40 and ERA-Interim total ozone data on days with missing measurements significantly improved completeness and reliability of the data series mainly in the first two decades of the period concerned. Consistent behaviour of the original and corrected/merged data sets was found in the pre-ozone-hole period (1961–1985). In the post-Pinatubo (1994–2010) era the data series show seasonal differences that can introduce uncertainty in estimation of ozone recovery mainly in the winter-spring season when the effect of the Montreal Protocol and its Amendments is expected. All the data sets confirm substantial depletion of ozone also in the summer months that gives rise to the question about its origin. The merged and completed data series of total ozone will be further analyzed to quantify chemical ozone losses and contribution of natural atmospheric processes to the ozone depletion over the region. This case study points out the importance of selection and evaluation of the quality and consistency of the input data sets used in estimation of long-term ozone changes including recovery of the ozone layer over the selected areas. Data are available from the PANGAEA database at doi:10.1594/PANGAEA.779819 .