GISS Surface Temperature of Earth (GISTEMP)

An Extract from The NASA GISTEMP Webpage

Image Courtesy NASA GISS

The Goddard Institute for Space Studies (GISS) Surface Temperature Analysis (GISTEMP) is an estimate of global surface temperature change.

Graphs and tables are updated around the middle of every month using current data files from NOAA GHCN v3 (meteorological stations), ERSST v5 (ocean areas), and SCAR (Antarctic stations), combined as described in our December 2010 publication (Hansen et al. 2010).

These updated files incorporate reports for the previous month and also late reports and corrections for earlier months.

News and Updates

See the GISTEMP News page for a list of announcements and NASA articles related to the GISTEMP analysis.

See the Updates to Analysis page for detailed update information.


Before contacting us, please check if your question about the GISTEMP analysis is already answered in the FAQ.

If the FAQ does not answer your question, please address your inquiry to Dr. Reto Ruedy.

Other researchers participating in the GISTEMP analysis are Avi Persin, Dr. Makiko Sato, and Dr. Ken Lo. This research was initiated by Dr. James E. Hansen, now retired. It is currently led by Dr. Gavin Schmidt.


When referencing the GISTEMP data provided here, please cite both this webpage and also our most recent scholarly publication about the data. In citing the webpage, be sure to include the date of access.

Background of the GISS Analysis

The basic GISS temperature analysis scheme was defined in the late 1970s by James Hansen when a method of estimating global temperature change was needed for comparison with one-dimensional global climate models. The scheme was based on the finding that the correlation of temperature change was reasonably strong for stations separated by up to 1200 km, especially at middle and high latitudes. This fact proved sufficient to obtain useful estimates for global mean temperature changes.

Temperature analyses were carried out prior to 1980, notably those of Murray Mitchell, but most covered only 20-90°N latitudes. Our first published results (Hansen et al. 1981) showed that, contrary to impressions from northern latitudes, global cooling after 1940 was small, and there was net global warming of about 0.4 °C between the 1880s and 1970s.

The early analysis scheme went through a series of enhancements that are listed and illustrated on the History Page.

See the rest of this, in-depth NASA webpage and more starting at:

About GISS

The NASA Goddard Institute for Space Studies (GISS) is a laboratory in the Earth Sciences Division (ESD) of National Aeronautics and Space Administration‘s Goddard Space Flight Center (GSFC). The ESD is part of GSFC’s Sciences and Exploration Directorate.

NASA Goddard Institute for Space Studies
2880 Broadway
New York, NY 10025 USA

General inquiries about the scientific programs at NASA’s Goddard Institute for Space Studies may be directed to the Goddard Space Flight Center Public Affairs office at 1-301-286-8955.

Sea Surface Temperature (SST) | NOAA Resources

Online — Satellite SST is the longest and most mature application of ocean remote sensing. Passive observations are made with infrared (IR) sensors onboard multiple polar-orbiting and geostationary platforms, and microwave sensors onboard polar platforms.

The IR sensors have higher spatial (1-4 km) and temporal (10-15 min, onboard geostationary satellites) resolution, and superior radiometric performance.

However, IR sensors cannot “see through cloud”, thus typically limiting retrievals to ~20% of the global ocean, whereas microwave sensors may see through clouds (except heavily precipitating) and therefore have higher coverage, but have coarser spatial resolution (~20-50 km) and radiometric performance, cannot be used in coastal and marginal ice zone areas, and may be subject to other errors (due to e.g. radio frequency interference, RFI)

NOAA produces several L2 (Level 2) (original swath), L3 (gridded), and L4 (gap-free analysis) SST products in international Group for High-Resolution SST (GHRSST) Data Specifications version 2 (GDS2) and makes them available from NOAA CoastWatch:

Reference web page at NOAA:

Radiation thermometry: The measurement problem

Classic article by G. D. (Gene) Nutter from a NASA ARCHIVE

ASTM STP895 Cover
ASTM STP895 Cover (Image credit ASTM International)

This online article is very similar and covers most of the same materials as  “Radiation Thermometry — The Measurement Problem” delivered at a symposium sponsored by ASTM Committee E-20 on Temperature Measurement in cooperation with the National Bureau of Standards, Gaithersburg, MD on May 8, 1984.

This was subsequently published as the first chapter in the volume “Applications of Radiation Thermometry”, ASTM SPECIAL TECHNICAL PUBLICATION 895, J.C. Richmond, National Bureau of Standards and D.P. DeWitt, editors.


Radiation Thermometry—The Measurement Problem
Symposium Paper

January 1985 — STP895  STP38703S
The basic measurement problems of radiation thermometry are discussed, with emphasis on the physical processes giving rise to the emissivity effects observed in real materials. Emissivity is shown to derive from bulk absorptivity properties of the material. Blackbody radiation is produced within an opaque isothermal material, with partial internal reflection occurring at the surface.


Gene Nutter wrote this and many other  technical articles on the subject of radiation thermometry, including another classic , “A High Precision Automatic Optical Pyrometer in Temperatures ITS measurement and Control in Science and Industry, Vol. 4, 519-530, Instrument Society of America (1972).

Description: “An overview of the theory and techniques of radiometric thermometry is presented. The characteristics of thermal radiators (targets) are discussed along with surface roughness and oxidation effects, fresnel reflection and subsurface effects in dielectrics.

“The effects of the optical medium between the radiating target and the radiation thermometer are characterized including atmospheric effects, ambient temperature and dust environment effects and the influence of measurement windows.

“The optical and photodetection components of radiation thermometers are described and techniques for the correction of emissivity effects are addressed.”

NASA Info:Link to article:

Publication date 1988-03-01
Collection NASA_NTRS_Archive; additional_collections
Language English
Identifier NASA_NTRS_Archive_19880014512
Identifier-ark ark:/13960/t9h46mr2v
Ocr ABBYY FineReader 11.0
Pages 61

Ed Note (from the book jacket of the 1988 book “Theory and Practice of Radiation Thermometry”,  Edited by D.P. Dewitt and Gene D. Nutter, John Wiley & Sons, Inc.): “Gene D. Nutter is (was)  a senior staff member of the Instrumentation Center, College of Engineering, University of Wisconsin-Madison. He received his MS in Physics from  University of Nebraska and had been earlier associated with the National Bureau of Standards and Atomics International.”

Chapter 5 in the above referenced text is linked below below. a classic book on the theory & practices of radiation thermometry published in 1998. It was recently found on and at the following links: FOR ABOUT $349.

AND for between $353 and $453 on ebay at:


Earth as a Greenhouse

If you have problems understanding the science side of the (so called*) debate on Global Warming, consider Earth as a greenhouse**.

Whoops! It actually is!

Earth's global energy budget (PDF)
References: Trenberth, K. E., J. T. Fasullo, and J. Kiehl, 2009: Earth’s global energy budget (PDF). Bull. Amer. Meteor. Soc., 90, No. 3, 311-324,

Gases in the atmosphere that trap heat in the atmosphere are called greenhouse gases.

The USA’s Environmental Protection has an interesting webpage at that details the types of gases and their relative impact on Global Warming.

The most common and pervasive of these is, of course, Carbon Dioxide, known by its chemical designation CO2 and or the variation on that that is used by non-science types, CO2.

View the Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990–2015 (published 2017), developed by the U.S. Government to meet U.S. commitments under the United Nations Framework Convention on Climate Change (UNFCCC).

Visit the public comments page to learn more about comments EPA received on the public review draft of the 1990-2015 GHG Inventory report.

Prior year versions of the GHG Inventory are available on the U.S. Greenhouse Gas Inventory Archive page.

But, possibly unknown to the Administrator of EPA, the USA’s Department of Energy (DOE) has been working in the same area but with the objective of not only understanding sources and sinks of greenhouse gases like Carbon Dioxide, but with and eye to doing something about reducing it.

Here’s are some key links and a chart from the DOE website, Let’s hope that they don’t get “modified” in the pursuit of “political nonscience” – if this link vanishes, you’ll know – but in the interest of transparency we have copied the image and published it here.

The largest contributor to these emissions is from electricity production (73 percent).(click to learn more about sources and sinks)

The diagram depicting the stationary anthropogenic CO2 emissions by major industry is (from a DOE web page


Diagram depicting the stationary anthropogenic CO2 emissions by major industry.
The largest contributor to these emissions is from electricity production (73 percent).
(click to enlarge)

 Myth: Carbon dioxide comes only from anthropogenic sources, especially from the burning of fossil fuels.
Reality: Carbon dioxide comes from both natural and anthropogenic sources; natural sources are predominant.

Are the additional emissions of anthropogenic CO2 to the atmosphere impacting the climate and environment?

To learn more, search the web! The search engine that doesn’t track you and use your preferences in their business is and their search results for a search on “greenhouse effect” is at:


*In a real debate both sides are assumed to be sincere. Most of the Global Warming critics deny proven science and few, if any, can provide reproducible, alternate scientific basis for their arguments. They just argue, the last bastion of obstructionism.

Thus, the deniers “side” is widely suspected of being not only insincere, but also biased against the facts in order to avoid taking needed action and denying only out of some other agenda than saving mankind’s future.

Recently some politicians in the USA have grudgingly agreed that the Earth is warming but continue the denial of man’s influence and the need to reduce greenhouse gases. Thus inaction persists in the USA and other countries with deniers in power. 

However the rest of the civilized world has better science educated populous and elected representatives and they are making an effort to help slow the effects of greenhouse gases.



There are many specialized glossaries that cover the terms describing the unique details of temperature and moisture sensors and their uses and this page represents an attempt to index most of them and related topics, such as Meteorology, in one place.






Many online articles about radiation thermometry and its uses (infrared thermometers, radiation pyrometers) exist including technology articles, PowerPoint slide presentations and .pdf downloads, but they seem to be vanishing as more and more “big businesses” take over these specialized sensors.But few are aimed at being useful glossaries or definition of terms.

There are some exceptions and some well-crafted pieces that have been online for a while and can be found in semi-hidden corners of the Web.

Thermal Radiation Thermometers: temperature_measurement_radiation_thermometers

Thermal Imaging:  (Glossary of Basic Thermography Terms) .


American Meteorological Society’s (AMS) Glossary of Meteorology

The electronic version of the second edition of the AMS Glossary of Meteorology is a living document and meant to be periodically updated as terms in the field evolve. To that end, AMS has established a Chief Editor for the Glossary who is responsible for updating/revising existing terms and adding new terms. Learn more about the Glossary and current Editorial Board.

For recommendations on correctly citing and referencing the Glossary of Meteorology, please see the Glossary entry for Citation.

If you have any feedback or editing suggestions to the content in this Glossary, please contact the Chief Editor.

Glossary – NOAA’s National Weather Service

This glossary contains information on more than 2000 terms, phrases and abbreviations used by the NWS. Many of these terms and abbreviations are used by NWS forecasters to communicate between each other and have been in use for many years and before many NWS products were directly available to the public.

Glossary of Weather, Climate and Ocean 2nd Edition

ISBN: 9781935704799

Intended for educators, students and the public and inspired by increasingly interest in the atmosphere, ocean and our changing climate, this glossary provides an understandable, up-to-date reference for terms frequently used in discussions or descriptions of meteorological, oceanographic and climatological phenomena. In addition, the glossary includes definitions of related hydrologic terms.

Clearly this page is a work in progress, and it may be expanded in time. Priority will be according to the response it garners.

Understanding Radiation Thermometry Parts I & II

From NASA Technical Reports Server (NTRS)

From NASA Article
From NASA Article

In 2015, Timothy K. Risch of NASA developed two technical articles that are available on the NASA Technical Reports Server (NTRS).

Both articles may be freely downloaded from NTRS in various formats, as long as the NASA Server maintains their presence.

As far as we know these are royalty free and the only stipulation that NASA usually requires is an attribution. These are below in the form of links to the article on the NASA web site.

The articles are entitled:

Understanding Radiation Thermometry. Part I, 71 pages, publication date 2015-07-08, and Understanding Radiation Thermometry. Part II, 111 pages, same publication date.

We have reviewed these documents and find them to be an excellent summary of this temperature measurement method and have archived them on our site in two formats, mobi, suitable for reading on an E-reader and in Adobe pdf format.

Part 1 provides and Overview, Nomenclature, a bit about what temperature is and the history of measurement methods and delves into the physics underlying Radiation Thermometry.

Part II covers practical radiation thermometers, some detail on measurement techniques and calibration and a brief reference list.

These files are linked below many be freely downloaded as long as we maintain this website.

The NASA description for both article reads as follows:

This document is a two-part course on the theory and practice of radiation thermometry.

Radiation thermometry is the technique for determining the temperature of a surface or a volume by measuring the electromagnetic radiation it emits.

This course covers the theory and practice of radiative thermometry and emphasizes the modern application of the field using commercially available electronic detectors and optical components.

The course covers the historical development of the field, the fundamental physics of radiative surfaces, along with modern measurement methods and equipment.
NASA Technical Reports Server (NTRS) 20150021314 Understanding Radiation Thermometry. Part I NASA Technical Reports Server (NTRS) Free Download & Streaming Internet Archive

Understanding Radiation Thermometry – Part I pdf Format Timothy K. Risch NASA Armstrong Flight Research Center July 8, 2015

NASA Technical Reports Server (NTRS) 20150021315 Understanding Radiation Thermometry. Part II NASA Technical Reports Server (NTRS) Free Download & Streaming Internet Archive

Understanding Radiation Thermometry – Part II pdf Format Timothy K. Risch NASA Armstrong Flight Research Center July 8, 2015

Sources on the NASA Technical Reports Server:

The Use of Johnson’s Criteria for Thermal Infrared Camera & Systems Performance

Written by: Opgal staff writers  (August 03, 2017)

OPGAL Blog LinkOnline —  When customers are considering which thermal security camera or system to buy, one of the first questions asked of thermal imager manufacturers is usually: “At what distance can the IR camera detect a target?.

In other words, what is the camera’s ability to capture very small details at great distances?

When thinking about effective surveillance, it is indeed a good criterion to differentiate one sensor from another.

No matter which manufacturer you are buying from, the answer given to this question will almost always include the DRI ranges expression.

DRI refers to the distance at which a target can be Detected, Recognized, or Identified, based on certain universally accepted parameters.

In order to select the right sensor for your defense, security, or surveillance needs, these DRI ranges have to be, first, perfectly defined, but also assessed with regards to globally adopted industrial standards.

Enter: The Origin of Johnson’s Criteria

In 1958, at the first ever “Night Vision Image Intensifier Symposium”, John Johnson, a night vision scientist at the U.S. Army’s “Night Vision and Electronic Sensors Directorate” (NVESD), presented a paper named the Analysis of Image Forming Systems”.

Johnson’s paper defined a clear system with criteria and methodology for predicting an observer’s ability to find and assess targets using image intensifying equipment (such as thermal cameras), under various conditions. It worked well, and it was the first of its kind.

Johnson’s Criteria Definitions

Johnson’s model provided definitive criteria for calculating the maximum range at which “Detection, Recognition, and Identification (D, R, I)” could take place, with a 50% probability of success. (Orientation was also discussed, but this parameter is not used or recognized today).

Although newer methodologies for D,R,I exist today, such as NVESD’s “Night Vision Image Performance Model” (NV-IPM), the “Johnson’s Criteria” system was groundbreaking for its time, was the accepted standard in the defense industry for many years, and is still widely used in the security industry today.


Johnson defined “Detection” as the ability to subtend 1 TV line pair (+/- 0.25 line pairs) across the critical dimension of the subject (this translates to 2 pixels when using an LCD monitor). At the range that this occurs, regardless of target type, the observer could detect that a subject was in the field of view, 50% of the time. Today, many security camera companies loosely follow Johnson’s Criteria and define their camera’s “Detection” performance range as the ability to subtend either 1.5 or 2 pixels on the target, using various target sizes.


Johnson defined “Recognition” as the ability to subtend 4 TV line pairs (+/- 0.8 line pairs) across the critical dimension of the subject (this translates to 8 +/- 1 pixels when using an LCD monitor). At the range that this occurs, regardless of target type, the observer determines the type of subject, a human or a car for example, 50% of the time. Today many security camera companies typically define their cameras “Recognition” performance range as the ability to subtend 6 pixels on the target, using various target sizes.


Johnson defined “Identification” as the ability to subtend 6.4 TV line pairs (+/- 1.5 line pairs) across the critical dimension of the subject (this translates to 12 +/- 3 pixels when using an LCD monitor). At the range that this occurs, regardless of target type, the observer could detect the subject.

Today many security camera companies loosely follow Johnson’s Criteria and define their cameras “Identification” performance range as the ability to subtend 12 pixels on the target, using various target sizes.

Long range performance

Johnson’s Criteria in the Security Industry

DRI ranges, expressed in kilometers (or miles), can usually be found in the specification table of infrared camera brochures, or in a description of the cameras features. While a very helpful jumping off point for narrowing down the options and homing in on the best systems, customers would be doing themselves a disservice to only look at DRI.

This is because today the application of Johnson’s criteria varies somewhat across the security industry. In most instances, documentation uses simplified or modified versions of the criteria, but they do all generally follow similar rules.

Typically, most companies use twelve pixels on the target for identification, six for recognition, and two for detection (sometimes 1.5). However, the target size can vary greatly. Normally the defense industry “NATO” target size (2.3×2.3 meters) is used for calculating the performance range for detecting vehicles, but for a human target, various target sizes can be found.

It is important when selecting your thermal infrared camera to keep in mind that in any given document, the target size for a human can range from 1.7-1.83 meters tall and from 0.3- 0.75 meters wide, and factor this into your decision-making process.

The Need to look at the Bigger Picture

Because end-users often place a high value on the written specifications of the camera, marketing departments are under pressure to use performance calculations that make their cameras look better than the competitors. However, since these calculations typically do not take environmental factors into account, customers should ask their thermal camera providers to explain the other elements and benefits of each camera they are offering, and how they will perform in a variety of conditions.

A modified approach that considers parameters such as these can better help in choosing the right or system for your needs.

The post appeared first on

Using Thermal Infrared in “Furnace and Heater Tube Inspections”

by Ron Lucier, ASNT NDT Level III

(From the, September 27, 2017 with format altered for easier reading online – all text and images from IRInformIR)

ITC logo registered“One of the more challenging applications of infrared thermography is in the measurement of process heater and furnace tubes. In fact we get dozens of inquiries each year from our clients on this very subject.

“Since this is a very complex subject it is probably appropriate to start from the beginning.”

“Process Heaters”
There are as many uses for process heaters as there are designs. The basic configuration consists of a shell (outer casing), tubes (where the process fluid flows) and a heat source.

“These units are both thermodynamically and hydraulically complex.”

Process heater or furnace diagram

“In the simple drawing above we illustrate convective gas flow, which is turbulent, and radiant heat from the flame, refractory and other tubes – all non-uniform and time varying. When you view tube from an access port typically you can only see a portion of the tube or the tube at an oblique angle.

“Therefore, the odds are stacked against you from the start!”

“Why are heater tubes of interest anyway?”
Heater tubes 1“There are several reasons for inspecting tubes. Qualitatively slag (scale) buildup on the outside of the tube can be readily identified.

“Buildup on the inside of the tube (coking) is a bit more difficult but commonly performed.

“In both cases the slag or coke prevents the transfer of heat into the process fluid. In the case of slag buildup, the process fluid may not be sufficiently heated, affecting downstream processing.

“The case of coking on the inside of the tube is more serious. Since the coke has an increased resistance to heat transfer, the tube surface temperature increases.

“After all it is the flow of the process fluid that is keeping the tube “cool” in the first place.

“In fossil boilers this is called “DNB” – Departure from Nucleate Boiling and is usually caused by flame impingement, which initiates a layer of steam on the inside of the tube. The external tube surface, unable to conduct its heat to the water, increases dramatically, causing a failure (opening) in the tube.”

Read more »

ED NOTE: The SPIE has published a very useful and detailed book in its Tutorial Text Series entitled
Radiation Thermometry: Fundamentals and Applications in the Petrochemical Industry
Author(s): Peter Saunders (August 2007) that deals with this topic in depth from the point of view of non-contact temperature measurement (radiation thermometry). It contains a wealth of detail about the issues of slag and reflected thermal radiation as well as a useful tutorial on infrared temperature measurement.

It is available online at the SPIE bookstore at a modest price as both a softcover book and a pdf download.

The link is:

Here’s some details from the (above) linked SPIE web page:

Book Description

This tutorial text provides an introduction to the subject of radiation thermometry, focusing on sources of measurement error and giving advice on methods for minimizing or eliminating these errors. Topics covered include: blackbody radiation, emissivity, reflection errors, and atmospheric absorption and emission; commonly used radiation thermometer types; uncertainty calculation; and procedures for in-house calibration of radiation thermometers. Included is a chapter containing detailed measurement examples for a variety of furnace types and operating conditions found in the methanol, ammonia, and refining industries.

Book Details
Date Published: 3 August 2007
Pages: 176
ISBN: 9780819467836
Volume: TT78

Industrial temperature measurement | Basics and practice

Free Download From ABB

(Extract From the Introduction)

With this Handbook for industrial temperature measurements we are attempting to provide the technician with solutions to his wide variety of responsibilities. At the same time, it provides for those new to the field, insight into the basics of the most important measurement principles and their application limits in a clear and descriptive manner.

The basic themes include material science and measurement technology, applications, signal processing and fieldbus communication.

A practice oriented selection of appropriate temperature sensor designs for the process field is presented as well as therequired communication capability of the meter locations.

The factory at Alzenau, Germany, a part of ABB, is the Global Center of Competencefor Temperature, with numerous local experts on hand in the most important industrialsectors, is responsible for activities worldwide in this sector.

125 years of temperature measurement technology equates to experience and competence. At the same time, it forms an important basis for continued innovation.

In close cooperation with our customers and users, our application engineers create conceptsto meet the measurement requirements.

Our Sector-Teams support the customer, planner and user in the preparation of professional solutions.

Free download available online at:

Author Team:
Karl Ehinger, Dieter Flach, Lothar Gellrich, Eberhard Horlebein, Dr. Ralf Huck, Henning Ilgner, Thomas Kayser, Harald Müller, Helga Schädlich, Andreas Schüssler, Ulrich Staab,

ABB Automation Products GmbH

Many thanks to the publishing group at ControlEngineering-Europe for alerting us to this new online resource (

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If you can’t find the topic you seek, they may have already covered it.

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