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PRODUCT BRIEF
This product brief is an archived publication and may contain dated technical, contact, and link information
Publication Number:  FHWA-HRT-17-011     Date:  January 2017
Publication Number: FHWA-HRT-17-011
Date: January 2017

 

LTPP Climate Tool

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Publication No. FHWA-HRTM 2442, Pub 17-011
FHWA Contact: Larry Wiser, HRDI-30, (202) 493-3079, larry.wiser@dot.gov

This document provides an overview of the Long-Term Pavement Performance (LTPP) Climate Tool functionality.(1) Details are provided in the LTPP Climate Tool User Guide (FHWA-HRT-17-012).(2)

Objective

This Product Brief describes the Long-Term Pavement Performance (LTPP) Climate Tool (intended for use by infrastructure engineers) that provides convenient access to the National Aeronautics and Space Administration (NASA) Modern-Era Retrospective Analysis for Research and Applications (MERRA) climatic data.(1)

Introduction

The LTPP Climate Tool is an online tool hosted on LTPP InfoPave™ that provides users with access to processed versions of MERRA data using different visual features and interfaces.(1,3) MERRA is a global climate data reanalysis repository that combines computed model fields with the basic climatic data attributes.(4,5) The data have been collected globally from 1979 to the present at an hourly temporal resolution and a horizontal spatial resolution of 0.5 degrees latitude by 0.67 degrees longitude (approximately 50 by 65 km at mid-latitudes). Further details regarding the MERRA data can be found in the Federal Highway Administration (FHWA) publication Evaluation of LTPP Climatic Data for Use in Mechanistic-Empirical Pavement Design Guide (MEPDG) Calibration and Other Pavement Analysis.(6)

The LTPP Climate Tool offers users convenient access to climate data derived from the MERRA database in an intuitive and easy-to-use format.(1) The MERRA Climate Data for Mechanistic-Empirical Pavement Design Guide (MEPDG) Inputs button under the tools menu of the LTPP InfoPaveTM Web site allows users to extract the MERRA data in a format that is compatible with the American Association of State Highway and Transportation Officials AASHTOWare® Pavement ME Design software.(3,7,8)

Available Data

The climatic attributes available through the LTPP Climate Tool include temperature, precipitation, humidity, wind, and solar data.(1) The data elements available for each climatic attribute include the following:

The data are available in hourly, daily, monthly, and annual temporal resolutions. Data summaries, including average, maximum, minimum, standard deviation, and count, are provided for various elements.

LTPP Climate Tool Interface

The LTPP Climate Tool is composed of three modules: Location, Country, and Map.(1) These modules are used to select and download the desired data. The location module allows the user to select the desired data geographically, while the country module allows the user to select data based on country and State/Province for any country in the world. The map module provides geographic information service (GIS)-based files for all of the MERRA data cells for a selected year.

Location Module

The location module offers users multiple options for selecting geographic data. The single-point selection tool allows the user to select a single location on the map, and the corresponding data cell will be highlighted. The area selection tool allows the user to select an area consisting of multiple locations for which the climatic data can be extracted. The Climate Tool graphical interface is shown in figure 1.(1)

This is a screenshot of the Long-Term Pavement Performance (LTPP) Climate Tool taken from the LTPP InfoPave™ Web site. The Climate Tool graphical interface shows a map of North America with climate data selected by location. A dropdown selection box runs down the left side of the screen showing options for the user to choose what types of data to search under. The selections are organized under five headings: General, Structure, Climate, Traffic, and Performance. Under each major heading, there is a series of boxes to choose for more specific search criteria.

Figure 1. Screenshot. LTPP Climate Tool―select data by location.(1)

The search location bar allows the user to search for and access the required data for the geographic location by name. The user can also highlight one or more LTPP test sections by applying the filters on the left-hand side of the window and then using the single-point or area selection tool to highlight the data cell encompassing the LTPP test section(s).

Country Module

The country module allows users to select and extract data based on country and State/Province for any country in the world as shown in figure 2.

This is a screenshot of the Long-Term Pavement Performance (LTPP) Climate Tool taken from the LTPP InfoPave™ Web site. The user interface is shown when the data is selected by country. A legend runs down the left side of the data box and offers the user 10 different elements to search under. The box itself has three options to choose from at the top left side of the image: Location, Country, and Map. This image shows the Country tab selected. Below that, the user can key in the name of the country in a box to the left side of the tool and the State or Province name in a box to the right side of the tool. The figure displays the data selected for the United States and the State of South Carolina. Below those boxes are still more options for choosing data type. The current selections show data selected for the period of December 31, 2014, to December 31, 2015. Below that, there is a small check box to show more advanced data classification.

Figure 2. Screenshot. LTPP Climate Tool―select data by country.(1)

Map Module

The map module allows users to download GIS-based data files for all of the MERRA data cells for a selected data attribute and time frame. Files can be downloaded either in ESRI Shape File (*.shp) or Keyhole Markup Language (*.kml) format.

Data Extraction

The MERRA data selected using the location or country options can be downloaded for a specific time range, climatic attribute (temperature, precipitation, humidity, wind, or solar), and frequency (annual, monthly, daily, or hourly). These data can be obtained in a Microsoft® Excel (.xlsx) format file, a Microsoft® Access database (.mdb) format, or a Microsoft® SQL database (.bak) format.

A complete user guide is available in FHWA publication number FHWA-HRT-17-012.(2)

Contact Information

For questions about the LTPP Climate Tool, contact LTPP Customer Support Service Center at ltppinfo@dot.gov or submit questions using the customer support feature under the help tab of the menu bar of LTPP InfoPave™.(1,3)

References

  1. FHWA. LTPP Climate Tool, Federal Highway Administration, Washington, DC, obtained from: https://infopave.fhwa.dot.gov/data/climatetool, last accessed December 21, 2016.

  2. FHWA. (2016). LTPP Climate Tool User Guide, Report No. HRT-17-012, Federal Highway Administration, Washington, DC.

  3. Federal Highway Administration. LTPP InfoPave™, Federal Highway Administration, Washington, DC, obtained from: https://infopave.fhwa.dot.gov/, last accessed August 8, 2016.

  4. Rienecker, M.M., Suarez, M.J., Gelaro, R., Todling, R., Bacmeister, J., Liu, E., Bosilovich, M.G., Schubert, S.D., Takacs, L., Kim, G., Bloom, S., Chen, J., Collins, D., Conaty, A., Da Silva, A., Gu, W., Joiner, J., Koster, R.D., Lucchesi, A M., Owens, T., Pawson, S., Pegion, P., Redder, C.R., Reichle, R., Robertson, F.R., Ruddick, A.G., Sienkiewicz, M., and Woollen, J. (2011). “MERRA: NASA's Modern-Era Retrospective Analysis for Research and Applications,” Journal of Climate, 24(14), pp. 3624―3648.

  5. NASA. (2012). MERRA: Modern-Era Retrospective Analysis for Research and Applications, Goddard Space Flight Center, Global Modeling and Assimilation Office, Greenbelt, MD, obtained from: http://gmao.gsfc.nasa.gov/merra, last accessed March 9, 2015.

  6. Schwartz, C.H., Elkins, G.E., Li, R., Visintine, B.A., Forman, B., Rada, G.R., and Groeger, J.L. (2015). Evaluation of LTPP Climatic Data for Use in Mechanistic-Empirical Pavement Design Guide (MEPDG) Calibration and Other Pavement Analysis, Report No. FHWA-HRT-15-019, Federal Highway Administration, Washington, DC.

  7. AASHTO. (2015). Mechanistic-Empirical Pavement Design Guide: A Manual of Practice, Second Edition, American Association of State Highway and Transportation Officials, Washington, DC.

  8. AASHTO. (2015). AASHTOWare® Pavement ME Design Software, 2.2 Build 2.2.4, American Association of State and Highway Transportation Officials, Washington, DC.

Additional Information

Researchers―This study was performed by iENGINEERING Corporation.

Distribution―This Product Brief is being distributed according to a standard distribution. Direct distribution is being made to the FHWA Divisions and Resource Center.

Availability―The LTPP Climate Tool can be accessed via the LTPP InfoPaveTM Web site at https://infopave.fhwa.dot.gov/ under the data tab.

Key Words―MERRA, MEPDG, pavement performance, climate data, pavement design.

Notice ― This document is disseminated under the sponsorship of the U.S. Department of Transportation in the interest of information exchange. The U.S. Government assumes no liability for the use of the information contained in this document. The U.S. Government does not endorse products or manufacturers. Trademarks or manufacturers’ names appear in this report only because they are considered essential to the objective of the document.

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