UNITED STATES DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration Washington, D.C. 202130 ?1 1. e0 -. Q- our OFFICE OF LEGISLATIVE AFFAIRS October 27, 2015 The Honorable Lamar Smith . 7 Chairman Committee on Science, Space, and Technology 9, US. House of Representatives OCT 2 I 20l5 Washington, DC. 20515 0N SCIENCE Dear Mr. Chalrman: We are in receipt of your October 13, 2015, letter and subpoena requesting documents related to the study published by Thomas Karl, et al. in Science that refuted the notion that there has been a slowdown or hiatus in global warming over the 21St Century compared to the last half of the 20th Century. Please be assured that the National Oceanic and Atmospheric Administration (NOAA) continues to take the Committee?s oversight responsibilities very seriously. Indeed, we have endeavored over the past few months to answer all of the Committee?s questions about the data and to provide you with relevant and responsive information. To that end, we have: provided the Committee with the data it has requested, to the extent such data exist; provided citations to peer-reviewed articles that explain the methodology that NOAA scientists use to analyze the data; and explained how temperature is measured by various means and how such data must be corrected for non?climatic factors. Finally, at our own suggestion, we provided several of the scientists who authored the Karl, et al. study to brief Committee staff personally, one on June 16, 2015, and the second on October 19, 2015. The brie?ng that NOAA scientists provided to your staff on October 19, 2015 lasted over an hour and was extremely substantive. Our scientists travelled to Washington, DC. to meet with your staff in person. The scientists gave a presentation that covered: sources of surface temperature data; how data are used in monitoring and research; why datasets are corrected; an explanation of data from ships and data from buoys, and how and why buoy data is corrected to match ship data; an explanation of Night Marine Air Temperature (NMAT) and how it is used; other data used by NOAA (such as sea ice concentration data); and an explanation of satellite data and bulk atmospheric temperatures and how such data are used. Seven of your staff members attended the brie?ng. They asked questions throughout the brie?ng, and the NOAA scientists answered all of their questions candidly and clearl . At the brie?ng we had provided your staff with a PDF of the PowerPoint presentatiin; we are producing this PowerPoint with this letter as well. Primed on Recycled Paper It bears noting that the scientists? in-person presentation specifically addressed the questions that are the subjects of the three demands listed in your subpoena: (1) the methodology and utilization of NMAT to adjust ship and buoy temperature data; (2) the use of other global temperature datasets for both in?house dataset improvements and state of the climate reports; and (3) the utilization and consideration of satellite bulk atmospheric temperatures for use in global temperature datasets. As to the subject of the first demand in the subpoena relating to the methodology and utilization of NMAT to adjust ship and buoy temperature data, we have attempted to answer your questions several times. At the briefing, your staff asked if NOAA used NMAT in the dataset. The NOAA scientists explained that they use sea surface temperatures (SSTs) to calculate global average temperatures instead of NMAT because the coverage of NMAT is, at best, half as good as the sea surface temperature. They further explained that the United Kingdom Hadley Centre and National Oceanography Centre are the sources for the NMAT data that has been corrected for changes in NMAT measurement methods (this is not data produced by NOAA), and that these corrections are smaller than those required for SSTs from ship measurements. Our scientists informed your staff that NMAT data are used to identify and correct for non-climatic changes affecting ship SST measurements, such as the transition to measuring SST from using buckets of sea water to engine sea water intakes. Your September 10, 2015, letter requested NMAT data, and in our October 2, 2015, response to you, we provided links to both corrected NMAT data and uncorrected NMAT data, all of which are publicly available. The presentation again showed your staff where the corrected and uncorrected NMAT data could be accessed. In addition, with this letter, we are providing additional information, namely a published study from 2013, ?Global analysis of night marine air temperature and its uncertainty since 1880 the data set,? which describes the NMAT data NOAA uses to correct ship data for non-climatic changes in measurement methods. As to the subject of the second demand in the subpoena related to the use of other global temperature datasets for both in-house dataset improvements and ?press releases? conveying global temperatures to the public, we have also attempted to provide helpful explanatory information. During their briefing, our scientists clarified that the NOAA global climate reports always include ?press highlights? but that official press releases are typically reserved for the Annual State of the Climate Report or for other major findings. Our scientists explained to your staff what the global climate reports are; namely, they consist of collections of summaries recapping climate-related occurrences on a global scale. These reports contain, among other information, analysis of global land and ocean datasets and various maps showing selected significant climate anomalies and eve ts. The presentation illustrated this to your staff with a snapshot of the August 2015 obal Climate Report. With regard to the other data used by NOAA, our scientists described the sources of their land data (International Surface Temperature Databank and Global Historical Climatology Network) and ocean data (unadjusted SST and NMAT from the International Comprehensive Ocean Atmosphere Database, adjusted NMAT from the UK Met Office, and sea ice concentration data from NOAA National Centers for Environmental Prediction and the UK Met Office). Our scientists talked brie?y about how they hope to use new land data in January 2016. They also pointed out that in their Science paper they documented additional warming in the Arctic that has occurred over the past few decades but noted that they are still working on how to most effectively incorporate new data and methods to quantify this warming. In our August 20, 2015, letter to you, we provided links to several sources of data used in the Karl, et al. analysis, including Extended Reconstructed Sea Surface Temperature (ERSST) versions 3b and 4 for ocean areas and the Global Historical Climatology version 3 and the International Surface Temperature Databank for land areas. With this letter we are providing the following additional published studies and reports, some authored by NOAA scientists, which further explain how NOAA uses other global temperature datasets: ?Improvements to Historical Merged Land-Ocean Surface Temperature Analysis ?An Overview of the Global Historical Climatology Network Temperature Database?; ?Extended Reconstruction of Global Sea Surface Temperatures Based on COADS Data ?Extended Reconstructed Sea Surface Temperature Version 4 (ERSST.V4), Part I: Upgrades and Intercomparisons?; ?Extended Reconstructed Sea Surface Temperature Version 4 (ERSST.V4), Part II: Parametric and Structural Uncertainty Estimations?; Release 2.5: extensions and enhancements to the surface marine meteorological archive?; Merged Land-Ocean Surface Temperature Analysis?; ?An Overview of the Global Historical Climatology Network mean temperature data set, version ?Improved Extended Reconstruction of SST and ?The international surface temperature initiative global land surface databank: temperature data release description and methods.?1 As to the subject of the third demand in the subpoena concerning the utilization and consideration of satellite bulk atmospheric temperatures for use in global temperature datasets, we have also attempted to answer your questions. During the brie?ng, NOAA scientists discussed the satellite data used by NOAA, explaining to your staff how the Advanced Very High Resolution Radiometer and Advanced Microwave Scanning Radiometer data are used to help identify the geographic extent of above or below average SSTs that are important to know when calculating continuous fields from point measurements. Our scientists also discussed how NOAA and external partners collaborate on satellite datasets, and how satellite data, like data from other sources, must be corrected for non-climatic factors, such as changes in orbit, new satellites instruments, and instrument degradation on?orbit. There are several research teams that develop atmospheric bulk temperatures, one developed by Center for Satellite Applications and Research, and others developed by University of Alabama at 1 In October 2, 2015 letter to you, we provided links to some of these studies but now are producing PDFs of the papers for your ease in reviewing them. Huntsville (UAH), Remote Sensing Systems (RSS, which is a scienti?c research company), and the University of Washington. NOAA National Centers for Environmental Information funds the regular production of data from UAH and RSS. Atmospheric bulk temperatures are always discussed in the Annual State of the Climate Report, and they are occasionally discussed in the report during unusual events. Our scientists pointed out these data are not surface temperature measurements where we live, work, and grow our food, but rather re?ect temperatures many thousands of feet above the surface. We are providing with this letter the State of the Climate Report from 2014 to illustrate the application of bulk atmospheric temperature data (see page 813). NCAA scientists closed their brie?ng by stating that our goal is to put the best available scienti?c information into the hands of decision makers, and that global temperature product is another example of NCAA ful?lling that very important mission. We appreciate the Committee?s interest in these important issues, and we look forward to continuing to work with you and your staff. Sincerely, (gay/a Coby Dolan Director Of?ce of Legislative and Intergovernmental Affairs cc: The Honorable Eddie Bernice Johnson