I AIAA-2003-0894 10/15/02 ATMOSPHERIC MODELS FOR ENGINEERING APPLICATIONS Dale L. Johnson’ and Barry C. Roberts NASA Marshall Space Flight Center, Huntsville, Alabama 35812 William W. Vaughan University of Alabama in Huntsville, Huntsville, Alabama 35899 C. G. Justus Computer Sciences Corporation, Huntsville, Alabama 35824 ABSTRACT performance calculations, aircraft and rocket design, ballistic tables, etc.. Later some countries, notably the This paper will review the historical development of United States, also developed and published “Standard reference and standard atmosphere models and their Atmospheres”. The term “Reference Atmosphere” is applications. The evolution of the U.S. Standard used to identify vertical descriptions of the atmosphere Atmosphere will be addressed, along with the Range for specific geographical locations or globally. These Reference Atmospheres and, in particular, the NASA were developed by organizations for specific Global Reference Atmospheric Model (GRAM). The applications, especially as the aerospace industry began extensive scope and content of the GRAM will be to mature after WWII. The term “Standard Atmosphere” addressed since it represents the most extensive and has in recent years also been used by national and complete “Reference” atmosphere model in use today. international organizations to describe vertical Its origin was for engineering applications and that descriptions of atmospheric trace constituents, the remains today as its principal use. ionosphere, atomic oxygen, aerosols, ozone, winds, water vapor, planetary atmospheres, etc. 1. INTRODUCTION A standard unit of atmospheric pressure is defined as that pressure exerted by a 760 millimeter Since the mid lgth century there has been column of mercury at standard gravity (980.665 ems-*) at considerable effort devoted to the development of 45.5425” N latitude and sea level at a temperature of standard and reference atmosphere models. The first 273.15” K (Oo C). The recommended unit for “Standard Atmospheres” were established by meteorological use is 1013 .25 hectopascals (millibars). international agreement in the 1920’s. Later some Standard temperature is used in physics to indicate a countries, notably the United States, also developed and temperature of 0” C, the ice point, and a pressure of one published “Standard Atmospheres”. The term standard atmosphere (10 1 3.25 hectopascals). In “Reference Atmospheres” in used to identify atmosphere meteorology, the term standard temperature has no models for specific geographical locations. Range generally accepted meaning, except that it may refer to Reference Atmosphere Models developed during the the temperature at zero pressure-altitude in the standard 1960s are examples of these descriptions of the atmosphere (15” C) with a density of 1225.00 gm”. The atmosphere. The NASA Global Reference Atmospheric standard sea-level values of temperature, pressure, and Model (GRAM) is the optimum reference atmosphere density that have been used for decades are: and is global in extent. This paper discusses the various temperature of 288.15” K, or 15” C; pressure of 1013.25 atmospheric models, scopes, applications and limitations millibars, or 760 millimeters of Hg; and density of relative to use in aerospace industry activities. 1225.00 gmS3. As early as the middle of the lgth century, a Standard Atmosphere was needed as a basis for 2. HISTORICAL DISCUSSION calibrating aneroid barometers used in measuring altitudes. These instruments provided the means of A “Standard Atmosphere” is defined as a vertical obtaining a rough measure of the height of mountains distribution of atmospheric temperature, pressure, and and other land areas. They were later used for altitude density which by international agreement is taken to be determination in manned balloon flights. Similar representative of the Earth’s atmosphere. The first atmospheres in England as well as in the United States “Standard Atmospheres” established by international were computed on the basis of a constant temperature agreement were developed in the 1920’s primarily for independent of altitude. Shortly after the beginning of the purposes of pressure altimeter calibrations, aircraft 20th century, several atmospheres were developed on the basis of observed or assumed temperature-altitude profiles, in which the temperature decreased with increasing altitude. These atmospheres were adopted ’ Corresponding author address: Dale Johnson, NASA, by France, Italy, and Germany. The development of the Marshall Space Flight Center, Huntsville, AL 35812; e- airplane, plus the desire to improve the direct reading mail: dale.johnson @ msfc.nasa.gov accuracy of barometer altimeters, stimulated the measurement of atmospheric temperature to the The portion of the U. S. Standard Atmosphere greatest possible altitude at various locations, up to 32 km is identical with the ICAO Standard particularly in England, France, Germany, and Italy. Atmosphere, 1964; and identical below 50 km with the With the more general use of airplanes during IS0 Standard Atmosphere, 1973. For this reason, in World War I from 1914 to 1917, the need for one addition to providing an excellent description of the standard atmosphere to serve as the basis for atmosphere model development extending beyond comparison of aircraft performance became evident. The conventional aircraft operations, the U.S. Standard general international desire for unity of national Atmosphere, 1976 is used here to illustrate the vertical atmospheres following the end of World War I, as well as distribution of atmospheric temperature. Figure 1 the unreality and complexity of several of the existing provides an illustration of the temperature-height profiles aeronautical atmospheres, prompted the study of the to 100 km of the COESA U. S. Standard Atmosphere, problem with the aim of recommending a simple 1976, and the lowest and highest mean monthly compromise model. The result of this study was the temperatures obtained for any location between the adoption of an atmosphere model for France in 1920 as Equator and pole. the official standard atmosphere in aircraft performance For altitudes above approximately 100 km, tests. Italy also adopted this atmosphere model in 1920 significant variations in the temperature, and thus and England in 1921. It was not until 1925, however, that density, occur due to solar and geomagnetic activity over this atmosphere model was adopted in England as the the period of a solar cycle. Variations in the basis for altimeter calibration. In 1924 the International temperature-height profiles for various degrees of solar Commission for Aerial Navigation (ICAN) adopted the and geomagnetic activity are presented in Figure 2. model as the basis for an international standard known Profile (A) gives the lowest temperature expected at as the ICAN Standard Atmosphere. Though never solar cycle minimum; profile (B) represents average adopted by the United States (U.S.), this standard conditions at solar cycle minimum; (C) represents served much of the world until 1952 when slight average conditions at a typical solar cycle maximum; differences were reconciled and it was modified slightly and (D) gives the highest temperatures to be expected under the International Civil Aviation Organization during a period of exceptionally high solar and (ICAO), which included the United States. This standard geomagnetic activity. atmosphere formed the basis of the tables given in In the early 1970’s, during the initial National Advisory Committee for Aeronautics (NACA) development of the Space Shuttle vehicle, it was Report 1235. determined that the various reference atmosphere In 1922 the United States NACA Standard models developed up to that time frame might not be Atmosphere (or first U. S. Standard Atmosphere) was sufficient to use for a vehicle which could land at any published. It was officially approved on 2 December location on the Globe. This prompted the development 1924 by the Executive committee of NACA as described of the NASNMSFC Global Reference Atmosphere in NACA TR-218. The War and Navy Departments, the Model (GRAM), and its many revisions. GRAM gives Weather Bureau and the Bureau of Standards adopted it the engineer a monthly average atmospheric profile for use in aeronautical calculations. Table 1 gives a time (thermodynamic parameters and wind), with their history of the documented technical reports dealing with variability, either at any given lat/long location or along the updates to this U.S. Standard Atmosphere. In 1952 any inputted trajectory. GRAM-99 will be described in the International Civil Aeronautical Organization (ICAO) more detail in the next section. produced the ICAO Standard Atmosphere and in 1964 In 1996 the American Institute of Aeronautics an extension to 32 km. Subsequent to this time there and Astronautics (AIM) published a Guide to Reference have been a succession of Standard and Reference and Standard Atmosphere Models. This document Atmospheres, some extending to altitudes above 1000 provides information on the principal features for a km, produced by the U.S. Committee on Extension to number of global, regional, middle atmosphere, the Standard Atmosphere (COESA), Committee on thermosphere, test ranges, and planetary atmosphere Space Research (COSPAR), Comitet Standartov models. Summary information on these reference and (USSR), International Standardization Organization standard atmosphere models is given relative to (ISO), U. S. Air Force Research and Development geographic region, altitude range, parameters, species, Command (ARDC), U. S. Range Commanders Council temporal variation, output data, and principal application. (RCC), and U. S. National Aeronautics and Space The NASA Standards Program Handbook (NASA- Administration (NASA) plus others. COESA was HDBK-1001) dated August 2000 and entitled: established in 1953 and led to the publication of the “Terrestrial Environment (Climatic) Criteria Handbook for 1958, 1962, 1966 and 1976 versions of the U.S. Use in Aerospace Vehicle Development” contains a Standard Atmosphere. Section 3 entirely devoted to “Thermodynamic In 1975 the International Standards Properties and Atmospheric Models”, It can be viewed Organization published a Standard Atmosphere for and downloaded at : http://standards.nasa.gov. altitudes from -2 to 50 km that is identical to the ICAO Currently some of the most commonly used Standard Standard Atmosphere from -2 to 32 km. Subsequently and Reference Atmospheres include the ICAO Standard the IS0 published in 1982 a family of five Reference Atmosphere, 1952/1964, the IS0 Standard Atmosphere, Atmospheres for Aerospace Use for altitudes up to 80 1975, the U. S. Standard Atmosphere, 1976, the km and latitudes of 15, 30,45,60, and 80” N. COSPAR International Reference Atmosphere (CIRA), 2 1986 *, the NASNMSFC Global Reference Atmosphere That ambient density values presented here statistically Model (GRAM), 1999 ** and the RCC/MG Range exceed the 2-sigma boundaries as one would expect. Reference Atmospheres (see Table 2 for a complete Copies of the GRAM-99 document or computer code are Range listing). *** available upon request to Dale Johnson at NASA MSFC, Huntsville, AL 35812 , dalejohnson @msfc.nasa.gov. 3. GRAM-99 REFERENCE ATMOSPHERE 4. CONCLUSION The NASA-MSFC Global Reference The intent of this paper is to present a summary Atmospheric Model (GRAM) was developed for use by historical account regarding the establishment of design engineers, mission planners, or atmospheric International and domestic Standard and Reference investigators as a world-wide reference atmospheric Atmospheres. These atmospheres were developed to model (see Figure 3). It was last revised in 1999. provide a standard type of atmospheric input for the GRAM presents realistic monthly atmospheric and wind various aeronautical and space vehicle design, vertical profiles (up to 2500 km altitude), or values over development, and operational applications. The NASA any global location or along any path or trajectory Global Reference Atmospheric Model (GRAM-99) has desired. The parameters variability about the monthly been presented as an example of a unique, global, multi- mean Is also derived. The second capability of GRAM is dimensional reference atmospheric model, including its its ability to generate many Monte-Carlo type of realistic characteristics and engineering applications. atmospheric or wind realizations which obey the equations of the atmosphere. GRAM-99 uses the GUACA (0-27km), MAP (20-120km) and MET-99 This paper is an update of the Johnson et. al., (>90km) over its altitude ranges. Eleven atmospheric “Reference and Standard Atmosphere Models” paper constituents can also be obtained from GRAM. A presented at the loth AMS Conference on Aviation, variable-scale perturbation model provides both large- Range, and Aerospace Meteorology. scale (wave) and small-scale (stochastic) deviations from the mean values for thermodynamic variables and horizontal and vertical wind components. The small- 5. BIBLIOGRAPHY OF DOCUMENTS, INCLUDING scale perturbation model includes improvements in REFERENCES THEREIN, ON WHICH THE representing intermittency (“patchiness”). A major new CONTENTS OF THIS ARTICLE IS BASED feature in GRAM-99 is an option to substitute Range Reference Atmosphere (RRA) data for conventional Champion, K.S.W., 1995: Early Years of Air Force GRAM climatology when a trajectory passes sufficiently Geophysics Research Contributions to Internationally near any RRA site. GRAM can be run as a stand-alone Recognized Standard and Reference Atmospheres. program or as a subroutine in various engineering Technical Report PL-TR-95-2164, Air Force Phillips programs. Laboratory, Hanscom AFB, MA, USA. An example of the GRAM-99 capability for engineering use is shown in Figures 4, 5, and 6. These Johnson, D.L., 2000: Terrestrial Environment (Climatic) figures present a realistic X-37 descent trajectory lat/long Criteria Handbook For Use In Aerospace Vehicle (fig. 4) from a 57 degree inclination orbit in January with Development, NASA Standards Program, NASA-HDBK- a landing at Edwards AFB California. Vehicle altitude 10 01, httD://standards.nasa.aov. and time into re-entry are indicated in the figure. Figure 5 gives the mean January atmospheric density field (as Johnson, D.L., B.C. Roberts and W.W. Vaughan, 2002: a ratio of the U.S. Standard Atmosphere 1976 density) in Reference and Standard Atmosphere Models, which the vehicle’s trajectory will traverse when proceedings of 10” AMS Conference on Aviation, descending. Range, and Aerospace Meteorology, Portland OR, 13-16 Figure 6 presents the monthly variability (2- May 2002. sigma density envelopes) of the ambient density along this same trajectory, with one random Monte-Carlo Justus, C.G., D.L. Johnson, 1999: The NASNMSFC density perturbation realization as shown in this figure Global Reference Atmospheric Model - 1999 Version (also as a ratio of the U.S. 1976 density). One can (G RAM-99), NASMM-1999-209630. observe its variability along the given trajectory, and note Sissenwine, N., M. Dubin, and S. Teweles, COESA Co- chairmen, 1976: U. s. Standard Atmosphere, 1976. previously issued as ClRA 1961, ClRA 1965 and Stock No. 003-017-00323-0, U. S. Government Printing ClRA 1972. Office, Washington, D. C. USA. ** previously issued as GRAM-86, GRAM-88, GRAM-90 and GRAM-95. Vaughan, W.W., D.L. Johnson, C.G. Justus, and S. *** Some site specific annual reference atmospheres Pavelitz, 1996: Guide to Reference and Standard (and Hot and Cold atmospheres) have been created Atmosphere Models. Document ANSVAIAA G-003A- by NASNMarshall Space Flight Center for NASA 1996, American Institute of Aeronautics and sites of interest, as for Patrick AFB/NASA Kennedy Astronautics, Reston, VA, USA. Space Center, Vandenberg AFB and Edwards AFB. 3 . w ' 0 L TABLE 1. Timeline History of U.S. Standard TABLE 2. Listing of Published IRlG 81 RCC Range Atmosphere Publications. Reference Atmospheres. I I Date Title ReportNo. Author 1. Argentia, New Foundland 1922/6 1 Notes on the I NACATN- Diehl 2. Ascension Island, South Atlantic 3. Barking Sands, Hawaii Standard 99 4. Cape Canaveral, Florida Atmosphere 5. China Lake, California 1922 Standard NACA Rpt- Gregg 6. Dugway Proving Ground, Utah Atmosphere 147 7. Edwards AFB, California I (SA) 8. Eglin AFB, Florida 1925 I Standard I NACARpt- Diehl 9. Eniwetok, Marshall Islands, Pacific Atmosphere 10. Fairbanks, Alaska 11. Fort Churchill, Canada Tables & Data 12. Fort Greeley, Alaska NACA Rpt- Brombacher 13. Fort Huachuca, Arizona Calibrating 14. Johnston Island, Pacific I I Altimetersetc 15. Kodiak, Alaska 1932 I Some 1 NACARpt- Diehl 16. Kwajalein, Marshall Islands, Pacific Approximate 376 17. Lihue Kauai, Hawaii Equations for 18. Nellis AFB, Nevada 19. Point Arguello, California the Std Atmos 20. Point Mugu, California 1936 Altitude- NACA Rpt- Brombacher 21. Roosevelt Roads, Puerto Rico pressure Tables 538 22. Shemya, Alaska Based on US 23. Taguac, Guam, Pacific I Std Atm 24. Thule, Greenland 1947/1 I Tentative I NACATN- Warfield 25. Vandenberg AFB, California Tables for the I 26. Wake Island Pacific 27. Wallops Island, Virginia Prop of Upper 1200 I 28. White Sands, New Mexico Atmosphere 1954/5 I Manual of ICAO I NACA TN- Anon 29. Yuma PG, Arizona I I Std Atm Calc by 3182 I NACA 1955 I Standard I NACARD~- Anon I I 1 Atmosphere- 1 Tables to 1235 I 65800' 1956/12 1 The ARDC I AFSG Minzner 80 Model TN56-204 ttgsphere, #86 70 E Y 1958 US Extension to USGovPO Minzner - ICAO Std Atm I to 300 km 1959/8 I The ARDC I AFCRC Minzner I I Model TR59-267 Atmosphere, #115 I 1 1959 1962/12 I US Standard I USGovPO Anon I I AtmosDhere. 1962 1966 US Standard USGovPO Anon 20 Atmosphere Supplements, 10 1966 1976 The 1976 NASA SP- Minzner 0 Standard 398 120 140 160 180 200 220 240 260 280 300 320 Atmos. Above I I 86-km Altitude TEMPERATURE, K 1976 1 US Standard I USGovPO Anon FIGURE 1. Range Of Systematic Variability Of Atmosphere, Temperature Around The U. S. Standard 1976 Atmosphere, 1976 (Source U.S. Standard Atmosphere, 1976) 4 500 A) Ground Track of X37 Re-Entry Trajectory Landng st Ed*& RB from 57 degree Indination Orbi 55 50 .c 400 0 45 E :(I) 4 0 Y L ui :0 3 5 a i c3 '- 30 a3 300 I 25 CTiicrckl eMsa Erkvse rEyv 1e0w k 1m0 0in s Heecoignhdts . 1 2 a 2o !i E 130 140 150 160 170 180 190 200 210 220 230 240 250 260 $ Longitude, degrees East 0 200 FIGURE 4. Case 1 -January Ground Track for X-37 57' inclination orbit Re-entry Trajectory with Landing at Edwards AFB California. Re-entry Time and altitude are indicated. 100 -500 0 +500 +low TEMPERATURE DIFFERENCE, K FIGURE 2. Departures Of The Temperature-Altitude Profiles From That Of The U.S. Standard Atmosphere, 1976, For Various Degrees Of Solar Activity (Source: U. S. Standard Atmosphere, 1976) \- , 110 ... 100 90 80 E 70 gi 60 P 50 40 1x1 140 150 160 170 180 190 200 210 220 230 240 Longnude. degrees East FIGURE 5. Mean January Height vs. Longitude Cross-section of Atmospheric Density as a ratio of the US76 Density for the X-37 Case 1 Re-entry FIGURE 3. Schematic Structure of The NASA/MSFC Trajectory. Global Reference Atmospheric Model 1999 (GRAM- 99) 5 130 140 150 160 170 180 190 200 210 220 zy) 240 Longwud.. Chorrrs El* FIGURE 6. Mean January Atmospheric Density and 2-Sigma Density Envelopes vs. Longitude, and a Monte-carlo Density Perturbation Profile along the X- 37 Case i Re-entry Trajectory, as a ratio of the US. Standard 1976 Density. 6