Pursuant to a congressional request, GAO reviewed the joint acquisition of the Next Generation Weather Radar (NEXRAD) by the National Weather Service (NWS), Federal Aviation Administration (FAA), and Air Force, focusing on: (1) changes in acquisition and deployment plans; (2) the feasibility and cost of purchasing additional radars; (3) the Air Force contribution to the national NEXRAD network; and (4) the availability of Air Force and NWS NEXRAD.
GAO found that: (1) the three agencies reduced their original deployment plan from 175 radars to 163 radars because of changes in agency requirements, funding limitations, and military base closures; (2) the National Research Council (NRC) is studying the adequacy of proposed NEXRAD coverage; (3) NWS and the Air Force plan to deploy their radars by the end of fiscal year (FY) 1996, but FAA plans to delay deploying five of its radars until at least FY 1997 because of budget constraints; (4) because the option for purchasing additional radars is unpriced and subject to negotiation, additional NEXRAD could cost three times more than units currently under contract; (5) NWS has unrestricted access to Air Force NEXRAD, which provide essential backup, primary, and supplemental radar coverage; (6) all three agencies signed an agreement to operate all NEXRAD to satisfy the integrated needs of all three agencies; (7) Air Force radar availability data, which may be unreliable and overstated, indicate that some of its radars are performing below the tri-agency system availability requirements; and (8) NWS does not calculate operational availability for each NEXRAD site and it does not know if sites are meeting availability requirements.
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ASOS - Automated Surface Observing System
AWIPS - Advanced Weather Interactive Processing System
C4 - Command, Control, Communications, and Computer
CONUS - conterminous United States
DOD - Department of Defense
FAA - Federal Aviation Administration
GAO - General Accounting Office
GOES-Next - Next Generation Geostationary Operational Environmental Satellite
NEXRAD - Next Generation Weather Radar
NOAA - National Oceanic and Atmospheric Administration
NRC - National Research Council
NWS - National Weather Service
PUP - principal user processor
RDA - radar data acquisition
RPG - radar product generator
May 31, 1995
The Honorable Robert S. Walker Chairman
The Honorable George E. Brown, Jr. Ranking Minority Member
Committee on Science House of Representatives
This report responds to your request that we review the Next Generation Weather Radar (NEXRAD), a Doppler weather radar that the Departments of Commerce, Defense, and Transportation are jointly acquiring. As agreed, we focused on changes in the number of NEXRADs being deployed, contract options to purchase additional radar units, the Air Force's contribution to the national NEXRAD network, and the accessibility and availability of NEXRADs.
We are providing copies of this report to the Secretaries of Commerce, Defense, Transportation, and the Air Force; the Director of the Office of Management and Budget; and other interested congressional committees. Copies will also be made available to others upon request.
Please call me at (202) 512-6253 if you or your staff have any questions concerning this report. Major contributors are listed in appendix III.
Joel C. Willemssen
Director, Information Resources Management/Resources, Community, and Economic Development
Recent changes to the deployment schedule, uncertainties about the need for additional radars, and questions concerning interagency cooperation prompted the Chairman and Ranking Minority Member of the House Committee on Science to request that GAO determine (1) the NEXRAD units that were dropped from the original deployment plan and the reasons they were dropped, (2) the feasibility and estimated cost of extending the NEXRAD contract to purchase additional radars, (3) the Air Force NEXRADs' contribution to the national NEXRAD network and the accessibility of the Air Force NEXRAD data to civilian forecasters, and (4) the availability of the Air Force and NWS NEXRADs. Our objectives did not include determining the adequacy of national radar coverage because the National Research Council (NRC) is reporting separately on this issue.
NWS, the Air Force, and FAA currently plan to purchase and deploy 119, 30, and 14 NEXRADs, respectively, for a total of 163. As of February 1995, 107 radars had been deployed 81 by NWS, 22 by the Air Force, and 4 by FAA. Of the 163 planned radars, 144 are to be located at NWS and Defense sites within the conterminous United States (CONUS). These CONUS sites are to provide adequate geographic coverage of national weather events, thereby collectively supporting the three agencies' respective missions. The non CONUS radars are also to support the agencies respective missions at 19 selected locations in Hawaii, Alaska, the Caribbean, the Atlantic, the Pacific, and Korea. NWS relies on several of these 19 non CONUS radars to provide information about approaching off shore weather. FAA and the Air Force rely on many of these 19 radars to ensure safe aviation operations and resource protection.
A NEXRAD contract option exists to acquire up to 20 additional radars. These radars could be as much as three times as expensive as current units because manufacturer production lines have been shut down, and restarting them would involve considerable expense. NWS officials told GAO that the 163 radars will provide coverage equal to or better than the existing coverage. The 163 radars are expected to meet the needs of the three agencies, and the agencies do not plan to acquire additional NEXRADs. Therefore, NWS has not reassessed the cost effectiveness of acquiring additional radars under the contract option. However, the NRC study director stated that NRC expects to report on weaknesses in national coverage that may require NWS to buy additional radars, assuming that the benefits of doing so outweigh the associated cost.
According to NWS, the Air Force NEXRADs are essential to NWS' ability to issue quality forecasts and warnings because some provide the sole radar coverage for certain geographic areas, and all provide backup coverage in the event an NWS radar goes down. The Air Force does not restrict NWS forecasters' access to its radar data; however, Air Force data show that its radars are not available to the extent that the three agencies agreed is necessary. To make matters worse, the Air Force availability data are unreliable and appear to be overstated. Also, NWS does not know if its individual radars are available to the extent necessary because it does not monitor radar availability by site.
Also, FAA plans to place 5 of its 14 radars in storage until at least fiscal year 1997, and probably longer, because higher priority funding requirements are preventing FAA from paying the costs associated with deploying these radars. While these units are not located within CONUS, and thus do not affect NWS CONUS weather coverage, NWS officials said the radars are important to NWS' ability to issue timely and accurate forecasts and warnings. For instance, two of the radars located in the Caribbean would allow NWS to better track and monitor hurricanes as they approach the United States. However, NWS does not have a mission requirement for radar coverage outside CONUS.
NWS told GAO that the national radar coverage that is currently planned is equal to or better than existing coverage. However, the Secretary of Commerce, at the request of the House Committee on Science, Space, and Technology (now the House Committee on Science), commissioned NRC to study and report on the adequacy of proposed CONUS coverage compared to the existing coverage. The NRC study director said he expects the study to identify weaknesses in coverage and potential areas where additional radars may be needed. This report is to be issued in June 1995.
Program officials said they agreed to an unpriced option because no firm requirements for additional radars existed at the time the contract was negotiated. The contractor did not price the optional units because of the uncertainty of future costs (e.g., the costs of restarting subcontractor production lines).
NWS has no plans to buy additional radars, and as a result, has not reassessed the cost effectiveness of acquiring the more expensive radars. However, NRC is expected to report on national radar coverage that may warrant a reassessment of these plans.
In many cases, the Air Force NEXRAD operators and maintainers were not aware of the 96 percent availability requirement and, therefore, had no way of knowing that their performance was subpar. Inefficiencies in the Air Force's logistics process for obtaining spare parts have also made it difficult to meet availability requirements.
NWS also does not know if it is meeting the availability requirement for each of its units because it does not monitor availability on a site by site basis. Although NWS records radar downtime by site, it only uses this information to calculate the average availability of all sites, and it only monitors radar availability performance on this basis. It does not use this information to calculate and monitor site specific availability. While GAO agrees that these aggregate data are useful in monitoring such things as spare parts usage and maintenance staffing trends, the data do not disclose whether each radar meets the required 96 percent availability requirement.
not purchase additional radars to address any weaknesses in radar coverage that may result from the NRC study until assessing FAA's plans for deploying the five radars scheduled for storage and NWS' mission requirements for NEXRADs in these areas,
ensure that any radars bought in response to NRC's national radar coverage findings are cost beneficial, given that their unit cost could be substantially higher than those already purchased, and
analyze and monitor system availability data on a site specific basis for operational NEXRADs and correct any shortfalls in system availability that this analysis shows.
GAO also recommends that the Secretary of the Air Force direct the Air Force Director of Weather to improve the reliability of Air Force NEXRAD availability data and to correct any shortfalls that these data show.
The Department of Commerce generally concurred with GAO's findings, conclusions, and recommendations, and stated that NWS is taking steps to analyze and monitor system availability on a site specific basis. In a draft of this report, GAO proposed that the NOAA Assistant Administrator for Weather Services assess the operational impact of FAA delays in deploying the five radars and, on the basis of this assessment, take the necessary steps to ensure that NWS' radar coverage needs are met. In their comments, the Department of Commerce and the FAA NEXRAD program manager stated that NWS does not have a mission requirement for radars outside of CONUS. GAO has incorporated this comment in the section describing FAA plans for storing five radars and has revised the recommendation accordingly.
Commerce also partially concurred with the recommendation to ensure that any radars bought in response to NRC's coverage findings are cost beneficial. However, Commerce requested that the recommendation be modified to reflect only NWS core mission and the Weather Service Modernization Act requirements. The NRC study director told GAO that its study will only address NWS' core mission and the act and GAO, therefore, did not modify its recommendation.
The Department of Defense concurred with GAO's recommendation concerning the Air Force, and stated that it will develop management actions to improve NEXRAD availability and the reliability of Air Force data.
The National Weather Service's (NWS) basic mission is to provide weather and flood warnings, forecasts, and advisories for the protection of life and personal property. NWS operations also support other federal missions, such as aviation safety, and our nation's commercial interests, such as the agriculture industry. The Federal Aviation Administration (FAA) and the Air Force, besides being users of NWS data and information, also collect and analyze certain weather observations to support their respective missions. FAA, for example, collects and displays weather radar, cloud ceiling, and visibility data for its air traffic controllers to use.
Since the early 1980s, NWS has been modernizing its weather observing, information processing, and communication systems to predict the weather more accurately and quickly. This approximately $4.5 billion modernization consists of four major system acquisitions and several smaller system upgrades and developments. FAA and the Department of Defense (DOD) are collaborating with NWS on two of these major acquisitions the Next Generation Weather Radar (NEXRAD) and the Automated Surface Observing System (ASOS). In addition to improved weather predictions, NWS expects the modernization to permit it to streamline its operations and downsize its organization without a degradation of service. For example, it expects to reduce its number of field offices from about 250 to 118 and to reduce staffing levels from 4,700 to 3,900.
NEXRAD is being acquired jointly by NWS, the Air Force, and FAA. The three agencies currently plan to purchase and deploy 163 NEXRADs 119 for NWS, 30 for the Air Force, and 14 for FAA at an estimated cost of just over $1.4 billion $860 million from NWS, $264 million from the Air Force, and $293 million from FAA.
Of the 163 NEXRADS, 144 are to be located within the conterminous United States (CONUS),\4 11 are to be located in Hawaii and Alaska, and 8 are to be located in the Caribbean, the Atlantic, the Pacific, and Korea. Data from these radars are shared among the three agencies to support their respective missions. For example, NWS needs adequate CONUS coverage to issue timely and accurate forecasts and warnings, and uses data from several Air Force NEXRADs to fill some gaps in coverage. Likewise, the Air Force and FAA rely on NWS radars in addition to their own to support their respective national defense and aviation missions.
On the basis of the three agencies' collective mission needs and the Weather Service Modernization Act, which mandates that the Secretary of Commerce certify that there will be no degradation in radar coverage at the 10,000 foot level prior to closing, consolidating, automating, or relocating any of NWS' field offices, the three agencies negotiated the radars' locations to meet tri-agency radar coverage requirements. The locations of all CONUS radars are shown in figure 1.1.
(See figure in printed edition.)
To address this dilemma, NOAA evaluated the pros and cons of (1) reaching a comprehensive settlement with Unisys to deliver radar systems or (2) terminating the existing contract and contracting with another vendor. After analyzing both choices, NOAA and Unisys signed a comprehensive settlement of contractual issues in August 1991, renegotiated the contract, and the production of radars resumed. The renegotiated contract included a $182 million increase in the contract cost. The associated increase in the unit cost of the NEXRADs forced the Air Force to drop 13 units to remain within its program funding limits.
As of February 1995, 107 radars had been deployed 81 by NWS, 22 by the Air Force, and 4 by FAA. The final NEXRAD deployment is scheduled for June 1996. By September 1995, the three agencies are expected to have collectively spent $1.2 billion.
The RDA consists of a 10 centimeter wavelength Doppler weather radar that collects the raw data to, among other things, (1) measure wind velocity in severe weather, (2) provide improved estimates of precipitation amounts, and (3) track storm movement and intensity. The technology needed to perform this function includes an antenna, pedestal, radome (a dome shaped covering to protect the antenna), transmitter, and receiver. Included in the RDA unit is hardware and software necessary for a variety of control functions, including signal processing, monitoring, and error detection, as well as archiving the radar data. A computer processes the radar signals to create digital data that can be further processed by the RPG.
The RPG includes all hardware and software necessary for turning the data into displayable data products. Specifically, the RPG provides real time generation, storage, and distribution of products for users. It includes hardware and software required for system control; status monitoring; and error detection, archiving, and data processing.
The PUP is a workstation that consists of the hardware and software required for the request, display, local storage and annotation, and distribution of products by forecasters. It also includes the hardware and software required for local control, status monitoring, archiving, and communicating with other users. The PUP maintains a dedicated communication link to the RPG located on site, and it routinely receives NEXRAD products. The PUP also has the capability to access data from RPGs at other NEXRAD sites. In addition, under an NWS administered NEXRAD information dissemination service, NWS has set aside four communications ports to allow access by commercial companies that provide data to other government agencies and the public. Figure 1.2 shows the key NEXRAD subsystems for a typical NWS weather forecast office.
NWS' Office of Systems Operations will assume program management responsibility from the program office once all NEXRADs have been delivered. In addition, the Operational Support Facility provides technical support for operating and maintaining radar equipment. To ensure that the needs of all three agencies are met, both the program office and the Operational Support Facility are jointly staffed and funded by NWS, the Air Force, and FAA. NWS' National Logistics Supply Center in Kansas City, Missouri, will be the centralized NEXRAD depot and repair center for all three agencies' radars.
The Air Force owns all of DOD's NEXRADs, including four radars that are located at Army locations. The Director of Weather, Office of the Deputy Chief of Staff, Plans, and Operations, within the Air Force, is responsible for planning, programming, and budgeting for weather support. The Director of Weather's responsibilities include publishing weather policy and standardized procedures, and assessing the technical performance and effectiveness of Air Force weather support, including those associated with NEXRAD. The Director of Weather disseminates weather policy through the Air Force major commands,\8 which in turn distribute it to the Air Force bases responsible for the individual NEXRAD units. The Air Force is responsible for operating and maintaining DOD NEXRADs. The Air Force's Air Weather Service is the lead organization for oversight of all Air Force NEXRADs.
To determine which units have been dropped from the original deployment schedule and why they were dropped, we met with NEXRAD program officials to obtain the original and current deployment schedules, discuss which units were dropped or added to the deployment schedule, and identify the reasons why. In addition, we reviewed documentation on the 1991 comprehensive settlement, since this settlement led to the majority of the deployment changes. Finally, we verified our analysis of the units affected and the reasons why with NEXRAD program officials. We did not identify the impact of these changes because the National Research Council (NRC) is currently reviewing the adequacy of proposed NEXRAD CONUS coverage in terms of the "no degradation of service" requirement of the Weather Service Modernization Act.
To determine the feasibility and estimated cost of extending the NEXRAD contract to purchase additional radars, we reviewed the current contract option for additional radars. Since this option is unpriced, we obtained the program office's per unit cost estimate of acquiring radars if this option was exercised and compared this estimate to an oral estimate that the contractor provided to the program office.
To determine the Air Force NEXRADs' contribution to the national network, we reviewed the Federal Meteorological Handbook Number 11, published by the Office of the Federal Coordinator for Meteorology, to identify the types of data Air Force radars provide to NWS. In addition, we interviewed NWS and program officials to determine how NWS accesses and uses the Air Force radar data, and the impact of NWS not having the Air Force radar data. To determine the accessibility of the Air Force NEXRAD data to civilian forecasters, we interviewed program office, NWS, and Air Force officials about potential data restrictions.
To determine the availability of the Air Force radars, we collected and reviewed availability data from the Air Force and NWS operational NEXRAD units and compared these data to the availability requirement specified in the NEXRAD Joint Operational Requirements document. We also interviewed officials from the Air Force's Air Weather Service at Scott Air Force Base near St. Louis, Missouri; the Air Force's Air Combat Command in Hampton, Virginia; NWS' Operational Support Facility and Weather Forecast Office in Norman, Oklahoma; and seven DOD bases that operate and maintain NEXRADs.
We performed our work primarily at the NEXRAD program office, and NOAA and NWS headquarters in Silver Spring, Maryland. Our work was performed from October 1994 to May 1995, in accordance with generally accepted government auditing standards.
As requested, the Departments of Commerce and Defense provided written comments on a draft of this report. These comments are in appendixes I and II. We obtained oral comments from senior FAA officials, including the NEXRAD program manager. The comments from Commerce, Defense, and FAA are presented and evaluated throughout the report.
Most of the 163 radars are to be deployed by the end of fiscal year 1996. However, FAA plans to delay deploying five of its radars until at least fiscal year 1997 because of budget constraints. While these radars are outside CONUS, NWS officials said they are important to NWS' ability to track and forecast severe weather.
Since the comprehensive settlement, NWS has added three radars and FAA has added one. In addition, the Air Force has added a requirement for one radar, deleted the requirement for another, and transferred ownership of one of its radars to NWS. The net result is the reduction of 12 NEXRADs. According to program officials, the 163 remaining radars will still satisfy the three agencies' collective requirements and provide radar coverage equal to or better than the existing service. Table 2.1 summarizes the three agencies' respective changes to the deployment plan.
Table 2.1 Changes to Worldwide NEXRAD Plan by Agency Comprehens Original ive Current deployment settlement Additional deployment Agency plan changes changes plan ------------ ---------- ---------- ---------- ---------- NWS 115 0 +4 119 Air Force 44 -13 -1 30 FAA 16 -3 +1 14
============================================================ Total 175 -16 +4 163 ------------------------------------------------------------
Table 2.2 Changes to NEXRAD Plan Within CONUS by Agency Comprehens Original ive Current deployment settlement Additional deployment Agency plan changes changes plan ------------ ---------- ---------- ---------- ---------- NWS 115 0 +4 119 Air Force 28 -2 -1 25 FAA 0 0 0 0 ============================================================ Total 143 -2 +3 144 ------------------------------------------------------------
Of the 23 changes, 3 related to NWS radars, 16 related to Air Force radars (11 overseas), and 4 related to FAA radars. Table 2.3 identifies the changes by agency, sites affected, type, and reason for each of the 23 changes.
Locations of and Reasons for Changes in
NEXRAD Deployment Schedule
Agency Site Change Reason -------- ------------------- -------- ------------------- Air Central Germany Deletion Budget constraint Force Air Eastern Germany Deletion Budget constraint Force Air Western Germany Deletion Budget constraint Force Air Aviano Air Base, Deletion Budget constraint Force Italy Air Crotone Air Base, Deletion Budget constraint Force Italy Air Camp New Amsterdam, Deletion Budget constraint Force Netherlands Air Zaragoza Air Base, Deletion Budget constraint Force Spain Air East United Kingdom Deletion Budget constraint Force Air West United Kingdom Deletion Budget constraint Force Air Clark Air Base, Deletion Base closure Force Philippines Air Yokota Air Base, Deletion Frequency Force Japan unavailable Air England Air Force Deletion Base closure Force Base, Louisiana Air Grissom Air Force Deletion Base closure Force Base, Indiana Air Nellis Air Force Deletion Requirement deleted Force Base, Nevada Air Fort Polk, Addition New requirement Force Louisiana Air Loring Air Force Transfer Base closure Force Base, Maine FAA McGrath, Alaska Deletion Requirement deleted FAA Bering Sea, Alaska Deletion Requirement deleted FAA Site to be Deletion Requirement deleted determined FAA South Shore, Hawaii Addition New requirement NWS Greer, South Addition New requirement Carolina NWS Jackson, Kentucky Addition New requirement NWS National Severe Addition New requirement Storms Laboratory, Norman, Oklahoma ------------------------------------------------------------
The Secretary of Commerce asked the NRC Committee on National Weather Service Modernization to perform this study. The NRC study director said he expects the study, which NRC plans to issue in June 1995, to identify potential areas where coverage is degraded and where additional radars may be needed. Because of NRC's study, we did not address the impact of the reduced number of radars on the three agencies' radar coverage objectives.
NWS did not plan to place NEXRADs in these locations because NWS does not have a mission requirement for radar coverage outside CONUS. However, according to NWS officials, data from planned NEXRADs in Alaska, Hawaii, and the Caribbean will be used by NWS to enhance its ability to provide timely and accurate forecasts and warnings. For instance, according to the NOAA Assistant Administrator for Weather Services, two of these radars in the Caribbean would allow NWS to better track and monitor hurricanes approaching the United States. Despite NWS' desire to have radars in these areas, the NOAA Assistant Administrator for Weather Services stated that should FAA decide not to deploy these radars, he is not sure whether NWS would choose to do so.
The Department of Commerce also stated that we did not accurately characterize the NRC study. Commerce stated the NRC study is of proposed NEXRAD radar coverage and consolidation of field offices to ensure the "no degradation of service" requirement of the Weather Service Modernization Act. We have clarified references to the NRC study in our report to state that the study is of proposed NEXRAD coverage as compared to premodernization radar coverage.
Commerce also noted that NOAA believes that the currently planned NEXRAD network will provide radar coverage equal to or better than the existing service, and that NOAA is aware of gaps in modernized radar coverage. Our report has been modified to reflect this.
Commerce also stated that the number of systems to be purchased and deployed still stands at 175, rather than the 163 we reported. It explained the disposition of the radars resulting from the comprehensive settlement. We agree with this explanation and have added a clarifying statement in this chapter. However, the number of systems to be deployed is 163. This number, which is based on our review of the NEXRAD deployment schedule, is consistent with program office documentation and with the total presented by the Under Secretary for Oceans and Atmosphere, before the Senate Subcommittee on Science, Technology, and Space, Committee on Commerce, Science, and Transportation in his January 31, 1995, testimony.
While the price of the additional NEXRADs, should they be required, will ultimately be subject to negotiation, the program office estimates that the hardware and software costs for each radar could be as much as three times that of the mean cost of radars currently under contract. The program office based this estimate on a recently expired, priced contract option that had a not to exceed price. It then factored in additional costs due to breaks in production. These disruptions increase costs because the longer the government waits to exercise the option, the greater the chances that the contractor and its subcontractors will have shut down part or all of their production lines and started work for other clients. According to program officials, this has already occurred as the subcontractor responsible for the transmitter has closed its production line.
The program office estimate is consistent with a nonbinding, verbal estimate that the contractor provided to the program office. This contractor estimate, however, assumed that the option would be exercised in the first quarter of fiscal year 1995. Exercising the option later, according to program officials, would result in a higher unit cost. In addition, the program office based its estimate on the purchase of 12 radars. Purchasing fewer radars would also increase the unit cost because manufacturing start up costs for a smaller order would be allocated over fewer units.
Office of Management and Budget Circular A 11 requires that agencies use benefit cost analyses to evaluate contemplated investments in information technology. The purpose of these analyses is to maximize an agency's return on its information technology dollar. In addition, these analyses are not to be one time exercises performed at the beginning of a project. Instead, it is fiscally prudent to redo these analyses whenever expected benefits or estimated costs change significantly. Without reassessing a system's payback in the event of sizeable cost growth, poor investment decisions can result.
As mentioned in chapter 2, weaknesses in NEXRAD's national coverage that are identified by NRC may suggest that NWS buy additional radars. Should this occur, the existing contract option would be an available vehicle for doing so, subject to applicable procurement regulations. The program office has not assessed the cost effectiveness of purchasing the additional units because currently no requirements exist for additional radars. If this changes, program officials agreed that it would be wise in deciding whether or not to exercise the contract option, to reassess the benefits to be derived from the additional radars against their higher cost.
In addition, Commerce stated that while the existing contract option is an available vehicle for buying additional radars should the need arise, it is by no means obvious that this vehicle would be exercised. Commerce added that under federal acquisition regulations, the government would have to determine the best approach for acquiring additional systems. We have modified the report to address these concerns.
NWS has unrestricted access to all Air Force, CONUS based NEXRAD products. According to a tri-agency agreement, all NEXRADs "shall be operated to satisfy the integrated needs of all three agencies." Further, each agency is to "support, to the maximum extent possible, the data, products, and operational requirements of the others, consistent with the capabilities and mission priorities of that agency." All CONUS Air Force sites are specifically required to "provide assistance to NWS offices by providing access to weather radar data for gaps in the National Weather Radar Network."
NWS' access to the Air Force's CONUS based NEXRADs is accomplished via dedicated and dial up communication lines. Currently, 13 weather offices have dedicated lines to Air Force NEXRADs. The 13 offices are generally the closest ones geographically to the Air Force radars. These dedicated lines operate at 9.6 kilobits per second. Each Air Force NEXRAD also provides three to four dial up communication ports for use by other NWS field offices. These lines are also 9.6 kilobits per second and are reserved for NWS use.
In its comments, the Department of Defense disagreed with our conclusion on the role Air Force radars play in the National Weather Radar Network. Specifically, Defense disagreed with our use of the term backup when associated with the Air Force's radars, because it implies that the Air Force's radars are integral parts of the national network. Defense stated that the tri-agency documentation defines NWS' radars as network sites and the Air Force's as supplemental sites, and that therefore we should not refer to the Air Force CONUS based NEXRADs as backup systems, but rather as supplemental sites.
We have decided not to use the term supplemental when referring to these Air Force radars because they provide primary, backup, and supplemental coverage. For example, the tri-agency documentation specifically states that CONUS based supplemental Air Force sites are to "provide assistance to NWS offices by providing access to weather radar data for gaps in the National Weather Radar Network." Today, 7 of the 22 CONUS based operational Air Force NEXRADs provide the sole radar coverage for certain geographic areas. NWS officials also told us that NWS uses data from Air Force NEXRADs to provide backup coverage and to supplement data from their NEXRADs, as well as to provide primary coverage. On the basis of this combination of primary, backup, and supplemental coverage, the Air Force CONUS based NEXRADs contribute considerably to the national NEXRAD network and are indeed integral parts of the national network.
Many of the Air Force's NEXRADs are not meeting the 96 percent availability requirement. Since January 1994, the reported percent of operational Air Force NEXRADs meeting this requirement each month has ranged from 38 to 90 percent (see figure 5.1).
Figure 5.1: Number of Air Force NEXRADs Meeting 96 Percent Availability Requirement
(See figure in printed edition.)
Note: Numbers in parentheses indicate the number of Air Force NEXRADs in operation.
However, the data upon which these availability statistics are based are unreliable and appear to be overstated. For example, the Air Force data provided by the Air Weather Service show that nine NEXRADs have been operationally available 100 percent of the time for 4 or more consecutive months. This is highly unlikely considering that, according to NWS' Chief Logistician, the radars are likely to fail an average of 52 times a year, or about 4 times per month. We contacted six of the nine sites reporting 4 or more consecutive months of 100 percent availability and found that three of the sites had significant outages during this time. For example, data for Eglin Air Force Base show 100 percent availability for September through December 1994, but Eglin radar officials stated that their radar was available for these 4 months only 87, 78, 79, and 87 percent of the time, respectively. Similarly, data for Dyess Air Force Base show 100 percent availability for February 1995, but Dyess officials stated that their radar was available only 81 percent of the time in February 1995. Also, data for Robins Air Force Base show 100 percent availability for September 1994, but Robins officials stated that their radar was unavailable for 12 days in September 1994 while they were waiting for a replacement part.
According to an internal Air Force report dated October 1994, the availability data inconsistencies are not unique to NEXRAD, but rather extend to all Air Force command, control, communications, and computer (C4) systems. The report stated that not all system performance data are being collected and reported on C4 systems. This occurs, according to the report, because C4 personnel do not adequately understand and are not sufficiently trained in the maintenance data collection process and because the systems collecting and reporting the performance data have software problems that have gone unchecked. The report recommends that the Air Force establish a team to address these problems.
This problem is even more severe for the four CONUS Air Force NEXRADs located near Army installations, where parts that are ordered are first sent to the nearest Air Force base, which records the transaction and then ships the parts to the Army base. The distance between the Air Force and Army locations varies from 90 to 330 miles, causing an additional delay of at least 4 to 12 hours. Air Force officials told us that they strive to keep their NEXRADs operational 100 percent of the time; however, the current system component failure rates and the logistics process Air Force NEXRAD sites must follow to obtain spare parts from NWS' National Logistics Supply Center make it difficult to achieve the 96 percent availability requirement. Figure 5.2 shows the additional steps required for the Air Force and Army NEXRAD sites to obtain needed spare parts.
Figure 5.2: NWS and Air Force NEXRAD Logistics Processes
(See figure in printed edition.)
NWS' Chief Logistician also identified several other logistics inefficiencies that contributed to the limited availability of the Air Force's NEXRADs. For example, until October 1994, the Air Logistics Center did not operate on evenings, nights, and weekends. Also, NWS did not have accurate and complete addresses for all Air Force NEXRAD sites, and thus parts would sometimes arrive at the base, but would not be delivered to the proper maintenance location. NWS' Chief Logistician stated that these problems have added days to the parts delivery process. Also contributing to the Air Force radars' availability shortfalls, according to the Chief Logistician, has been a limited supply of parts at Air Force NEXRAD sites.
To address these logistics concerns, NWS and Air Force officials established a logistics working group in September 1993. Members of this group stated that a number of the procedural problems have been eliminated. For example, they said that the group has automated the parts request process through the Air Logistics Center to the Office of Systems Operations so that parts orders can be placed 24 hours a day for emergency requisitions. They also said that the group provided NWS with complete addresses for all base supply organizations servicing Air Force NEXRAD sites. Also, they said that steps are underway to improve the stocking of on site spares. In addition to these initiatives, they cited steps underway to provide better service to remote Army NEXRAD sites. For example, the Air Force is examining whether a common carrier can deliver parts to Army NEXRAD sites more quickly.
While we agree that such data on availability are useful, aggregate data do not allow NWS to determine whether each radar meets the required 96 percent availability requirement. The Office of Systems Operations Director agreed that it was important to track availability by site, and said that NWS would monitor availability on a site by site basis in the future. However, this change has yet to occur, and a time frame for doing so has not been established.
We recommend that the Secretary of Commerce direct the NOAA Assistant Administrator for Weather Services to begin analyzing and monitoring system availability data on a site specific basis for its operational NEXRADs and correct any shortfalls in system availability that this analysis shows.
The Department of Commerce also concurred with our recommendation concerning the analysis and monitoring of system availability data on a site specific basis and stated that NWS is taking steps to allowing it to analyze and monitor system availability on a site specific basis.
(See figure in printed edition.)
(See figure in printed edition.)
(See figure in printed edition.)
Note: The Department of Commerce also included in its comments a statement that the existing contract option is an available vehicle for buying additional radars, and, thus, any references to the estimated costs of exercising this option are potentially acquisition sensitive. We have deleted this statement from the Department's comments because it identified the estimated unit cost.
Rona B. Stillman, Chief Scientist for Computers and Communications
Randolph C. Hite, Assistant Director
Keith A. Rhodes, Technical Assistant Director
David A. Powner, Evaluator in Charge
Shane D. Hartzler, Communications Analyst
Joseph P. Sikich, Staff Evaluator