Scott D. Woodruff

A Comprehensive Ocean-Atmosphere Data Set

Development is described of a Comprehensive Ocean-Atmosphere Data Set (COADS)—the result of a cooperative project to collect global weather observations taken near the oceans surface since 1854, primarily from merchant ships, into a compact and easily used data set. As background, a historical overview is given of how archiving of these marine data has evolved from 1854, when systematic recording of shipboard meteorological and oceanographic observations was first established as an international activity. Input data sets used for COADS are described, as well as the processing steps used to pack input data into compact binary formats and to apply quality controls for identification of suspect weather elements and duplicate marine reports. Seventy-million unique marine reports for 1854–1979 were output from initial processing. Further processing is described, which created statistical summaries for each month of each year of the period, using 2° latitude × 2° longitude boxes. Monthly summary products are a...

Extended Reconstructed Sea Surface Temperature Version 4 (ERSST.v4). Part I: Upgrades and Intercomparisons

AbstractThe monthly Extended Reconstructed Sea Surface Temperature (ERSST) dataset, available on global 2° × 2° grids, has been revised herein to version 4 (v4) from v3b. Major revisions include updated and substantially more complete input data from the International Comprehensive Ocean–Atmosphere Data Set (ICOADS) release 2.5; revised empirical orthogonal teleconnections (EOTs) and EOT acceptance criterion; updated sea surface temperature (SST) quality control procedures; revised SST anomaly (SSTA) evaluation methods; updated bias adjustments of ship SSTs using the Hadley Centre Nighttime Marine Air Temperature dataset version 2 (HadNMAT2); and buoy SST bias adjustment not previously made in v3b.Tests show that the impacts of the revisions to ship SST bias adjustment in ERSST.v4 are dominant among all revisions and updates. The effect is to make SST 0.1°–0.2°C cooler north of 30°S but 0.1°–0.2°C warmer south of 30°S in ERSST.v4 than in ERSST.v3b before 1940. In comparison with the Met Office SST product...

COADS Release 2 data and metadata enhancements for improvements of marine surface flux fields

Abstract The Comprehensive Ocean-Atmosphere Data Set (COADS) has been updated through a cooperative U.S. project since 1981, including vital international contributions. Quality controlled marine surface observations from ships have been supplemented in more recent years to include moored environmental buoys, drifting buoys, and near-surface measurements from oceanographic profiles. The data set now covers 142 years, 1854–1995. Monthly statistics of pseudo-fluxes and basic marine variables are calculated for each year using observed data falling within 2° latitude × 2° longitude boxes (1°×1° summaries are also available for 1960-93). Enhancements in data and metadata planned by the year 2000 as part of COADS Release 2 (∼ 1820–1997) will concentrate on the basic observational records. In addition to new data sources, which will augment flux estimates through expanded coverage, planned enhancements include: a) usage of selected metadata from WMO Pub. No. 47 (ship instrumentation history) to improve the observational records back to about 1973; b) improvements in the reliability of the wind speed (“estimated/measured”) indicator; and c) bias adjustments of wind speed Beaufort estimates and anemometer measurements.

Extended Reconstructed Sea Surface Temperature Version 4 (ERSST.v4): Part II. Parametric and Structural Uncertainty Estimations

Described herein is the parametric and structural uncertainty quantification for the monthly Extended Reconstructed Sea Surface Temperature (ERSST) version 4 (v4). A Monte Carlo ensemble approach was adoptedtocharacterizeparametricuncertainty,becauseinitialexperimentsindicatetheexistenceofsignificant nonlinear interactions. Globally, the resulting ensemble exhibits a wider uncertainty range before 1900, as well as an uncertainty maximum around World War II. Changes at smaller spatial scales in many regions, or for important features such as Nino-3.4 variability, are found to be dominated by particular parameter choices. Substantial differences in parametric uncertainty estimates are found between ERSST.v4 and the independently derived Hadley Centre SST version 3 (HadSST3) product. The largest uncertainties are over the mid and high latitudes in ERSST.v4but in the tropics in HadSST3. Overall, in comparison with HadSST3, ERSST.v4 has larger parametric uncertainties at smaller spatial and shorter time scales and smaller parametric uncertainties at longer time scales, which likely reflects the different sources of uncertainty quantified in the respective parametric analyses. ERSST.v4 exhibits a stronger globally averaged warming trend than HadSST3duringtheperiodof1910‐2012,butwithasmallerparametricuncertainty.Theseglobal-meantrend estimates and their uncertainties marginally overlap. Several additional SST datasetsare usedto infer the structuraluncertainty inherent in SST estimates. For the global mean, the structural uncertainty, estimated as the spread between available SST products, is more often than not larger than the parametric uncertainty in ERSST.v4. Neither parametric nor structural uncertainties call into question that on the global-mean level and centennial time scale, SSTs have warmed notably.

Metadata from WMO Publication No. 47 and an Assessment of Voluntary Observing Ship Observation Heights in ICOADS

It is increasingly recognized that metadata can significantly improve the quality of scientific analyses and that the availability of metadata is particularly important for the study of climate variability. The International Comprehensive Ocean–Atmosphere Data Set (ICOADS) contains in situ observations frequently used in climate studies, and this paper describes the ship metadata that are available to complement ICOADS. This paper highlights the metadata available in World Meteorological Organization Publication No. 47 that include information on measurement methods and observation heights. Changing measurement methods and heights are known to be a cause of spurious change in the climate record. Here the authors focus on identifying measurement heights for air temperature and wind speed and also give information on SST measurement depths.

MARINE OBSERVATIONS OF OLD WEATHER

Weather observations are vital for climate change monitoring and prediction. For the worlds oceans, there are many meteorological and oceanographic observations available back to the mid-twentieth century, but coverage is limited in earlier periods, and particularly also during the two world wars. Before 1850 there are currently very few instrumental observations available. Consequently, detailed observational estimates of surface climate change can be made only back to the mid-nineteenth century. To improve and extend this early coverage, scientists need more observations from these periods. Fortunately, many such observations exist in logbooks, reports, and other paper records, but their inclusion in the climatic datasets requires that these paper records be abstracted from the worlds archives, digitized into an electronic form, and blended into existing climate databases. As a first step in this direction, selected Royal Navy logbooks from the period of 1938–47, kept in the U.K. National Archives, ha...

The Evolving SST Record from ICOADS

Sea surface temperature (SST) is a key oceanic variable – widely used for research, including global climate change assessments and atmospheric reanalyses. This paper reviews the evolution of the SST data and products available from the International Comprehensive Ocean-Atmosphere Data Set (ICOADS), since that project’s inception in 1981. Climate-scale SST products based on ICOADS (or related in situ data) are also reviewed. Measurements of SST have been made since around the early 1800s from ships, augmented in recent decades by in situ measurements from buoys and other automated Ocean Data Acquisition Systems (ODAS). SST, unlike some other ICOADS variables such as surface air temperature or humidity, is observed from space with reasonable accuracy. However, without reference to in situ measurements most satellite-based SST products will contain large-scale biases due to varying atmospheric composition and imperfect instrumental calibration. ICOADS is vital to the removal of such biases, which are especially large following volcanic eruptions. We describe products combining in situ and satellite SSTs that exploit the strengths of each type of measurement, to yield both high resolution and high accuracy. Finally, we discuss future developments anticipated for ICOADS and SST products, such as further blending of metadata and enhanced product uncertainty assessments.

Toward an integrated set of surface meteorological observations for climate science and applications

AbstractObservations are the foundation for understanding the climate system. Yet, currently available land meteorological data are highly fractured into various global, regional, and national holdings for different variables and time scales, from a variety of sources, and in a mixture of formats. Added to this, many data are still inaccessible for analysis and usage. To meet modern scientific and societal demands as well as emerging needs such as the provision of climate services, it is essential that we improve the management and curation of available land-based meteorological holdings. We need a comprehensive global set of data holdings, of known provenance, that is truly integrated both across essential climate variables (ECVs) and across time scales to meet the broad range of stakeholder needs. These holdings must be easily discoverable, made available in accessible formats, and backed up by multitiered user support. The present paper provides a high-level overview, based upon broad community input, ...

Advances in the Use of Historical Marine Climate Data

SUMMARY OF DISCUSSION AND RECOM-MENDATIONS. Discussions were held in breakout groups, each focusing on a range of marine variables, and the following key conclusions were drawn:• An overarching recommendation was for con-tinuing augmentation of ICOADS with in situ marine meteorological data and enhanced links to ocean data repositories, such as the World Ocean Database (e.g., Levitus et al. 1998). At least 25 million undigitized ship logbook reports exist, for instance, in U.K. national archives. In view of scarce resources, the need for data inventories and assessments to help identify priorities for digitiza-tion and datasets for incorporation into ICOADS was also highlighted.• Concern was expressed that the marine obser-vation system is in decline. Observations from VOS have decreased by more than a half since 1990, and there are now fewer than a third of the number of VOS participating in the program. As a result, the uncertainty of in situ surface products is increasing. All of the discussion groups were concerned about the diminishing data quantities, which represent a huge challenge for the future. It is essential that the marine climate community makes assessments both of its future data require-ments and the adequacy of the surface marine climate observing system, and feeds this infor-mation through to the appropriate operational bodies.562 |

NOAA CIRES Twentieth Century Global Reanalysis Version 2

The Twentieth Century Reanalysis Project, supported by the Earth System Research Laboratory Physical Sciences Division from NOAA and the University of Colorado CIRES Climate Diagnostics Center, is an effort to produce a global reanalysis dataset spanning a portion of the nineteenth century and the entire twentieth century (1871 - near present), assimilating only surface observations of synoptic pressure, monthly sea surface temperature and sea ice distribution. Products include 6-hourly ensemble mean and spread analysis fields on a 2 by 2 degree global latitude-longitude grid, and 3 and 6-hourly ensemble mean and spread forecast (first guess) fields on a global Gaussian T62 grid. Fields are accessible in yearly time series (1 file per parameter) and monthly synoptic time (all parameters per synoptic hour) files. Ensemble grids, spectral coefficients, and other information will available by offline request in the future.\n\n The Twentieth Century Reanalysis Project used resources of the National Energy Research Scientific Computing Center managed by Lawrence Berkeley National Laboratory and of the Oak Ridge Leadership Computing Facility at Oak Ridge National Laboratory, which are supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 and Contract No. DE-AC05-00OR22725, respectively.\n\nNote: Version 2c of this reanalysis (running from 1851 - 2011) is the recommended research version. Please see ds131.2 to access Version 2c.