SOURCES SOUGHT
66 -- ASOS All Weather Precipitation Accumulation Gauges
- Notice Date
- 11/13/2008
- Notice Type
- Sources Sought
- NAICS
- 541690
— Other Scientific and Technical Consulting Services
- Contracting Office
- Department of Commerce, National Oceanic and Atmospheric Administration (NOAA), National Weather Service, 1325 East West Highway, SSMC2, Room 11226, Silver Spring, Maryland, 20910, United States
- ZIP Code
- 20910
- Solicitation Number
- NCAR111308
- Archive Date
- 12/23/2008
- Point of Contact
- Joyce J Dickerson,, Phone: 301-713-3405 ext 113, Anita R Middleton,, Phone: 301-713-3405 x167
- E-Mail Address
-
joyce.dickerson@noaa.gov, Anita.R.Middleton@noaa.gov
- Small Business Set-Aside
- N/A
- Description
- ASOS All Weather Precipitation Accumulation Gauges RFI The United States Department of Commerce, National Oceanic and Atmospheric Administration (NOAA), National Weather Service (NWS), Automated Surface Observing System (ASOS) Product Improvement Program intends to negotiate on a sole source basis, under authority of Federal Acquisition Regulation (FAR) Subpart 6.302 Other Than Full and Open Competition with National Center for Atmospheric Research (NCAR). Request for sole source is to support collection and analysis of data in order to develop a transfer algorithm to improve reporting accuracy of the ASOS All Weather Precipitation Accumulation Gauges (AWPAG) during periods of blowing precipitation. This effort will be conducted for approximately one year.The ASOS AWPAG is designed to accurately measure freezing and frozen precipitation in winter. A continuing concern with AWPAG performance is undercatch in wind driven snow conditions. Because the most common precipitation gauge installation has the gauge orifice elevated above ground level where it is impacted by airflow due to blowing wind. The resulting turbulence deflects falling hydrometeors, with the greatest effect being on low water content snow particles. This issue can be addressed by adding a wind screen of sufficient size to disburse the effects of blowing wind, however there is a practical limit to the size and resulting cost in installing large and expensive wind shields. The size can be a particular problem at airports where most NWS ASOSs are installed. A more practical approach is to develop a mathematical adjustment to the AWPAG report to account for wind effects. The approach to developing such an algorithm is to install a freestanding production AWPAG in close proximity to an AWPAG which is located inside a Double Fence Intercomparison Reference (DFIR) shield, a large wooden structure that is designed to optimize gauge catch to very close to the true catch. The ratio of AWPAG catch to DFIR catch can be correlated to wind speed and possibly other environmental factors to obtain a transfer function. While NWS has installed DFIRs in its testbed at Sterling, VA and its Winter Test Facility in Johnstown, PA, there is a requirement to collect performance data in a region where dry snows accompanied by strong wind are more common than at these two sites. The vendor must provide a facility having one or more existing DFIRs which meets this climatology requirement, and who has extensive additional precipitation measurement capabilities as well as extensive field test sensor and data acquisition capabilities. This facility must be instrumented such that accurate wind speed and direction, present weather and ambient temperature data is available. The NWS will be given access to all data collected that might be necessary or desirable for use in transfer function development. This may include but is not necessarily limited to: • Facility anemometer wind speed and direction at orifice and other heights • Measurements from other precipitation gauges installed in the testbed • Ambient temperature and dew point temperature valuesThis data would be made available by internet (e.g. ftp) such that NWS could download data daily. The vendor will assist in formulation and verification of the mathematical transfer function resulting from this effort. The goal of this task is to develop an AWPAG transfer function, a mathematical relationship of the catch ratio of the AWPAG with it's ASOS shield configuration to the catch of a precipitation gauge inside a Double Fence Intercomparison Reference as described in the WMO Report No. 67 (WMO/TD - No. 872,1998) WMO SOLID PRECIPITATION MEASUREMENT INTERCOMPARISON FINAL REPORT by B.E. Goodison and P.Y.T. Louie and D. Yang.Offerors who believe they can satisfy the requirement must demonstrate their ability in writing. All written response must include a written narrative statement of capability, facility description, including detailed technical information and other technical literature demonstrating the ability to meet the above requirements. The response must be sufficient to permit agency analysis to establish a bona fide capability to meet the requirements. Failure to submit documentation will result in the Government proceeding as stated above. A determination by the Government not to open the requirement to competition based upon responses to this notice is solely within the discretion of the Government. Affirmative written responses must be received no later than ten (10) days after publication to this synopsis to Joyce.Dickerson@noaa.gov or fax 301-713-1024. No telephone requests will be honored. Award will be made under commercial simplified acquisition procedures, FAR Subpart 12. ASOS All Weather Precipitation Accumulation Gauges SOW Statement of Work for installing an Automated Surface Observing System (ASOS) All Weather Precipitation Accumulation Gauge (AWPAG) within a Double Fence Intercomparison Reference (DFIR) to develop a Transfer AlgorithmBackground:The Automated Surface Observing System (ASOS) is the primary observing system for the National Weather Service (NWS). ASOS is configured to provide a complete automated aviation observation in support of flight operations at over 1000 airports throughout the U.S. About 330 of these ASOSs are also NWS first order stations for the additional purpose of providing accurate long term climate records. These stations have been upgraded with enhanced precipitation measurement capability. Specifically the All Weather Precipitation Accumulation Gauge (AWPAG) is designed to accurately measure freezing and frozen precipitation in winter. It has replaced the heated tipping bucket, which is not designed to measure winter precipitation. One continuing concern with the new AWPAG gauge is the well known problem of undercatch in wind driven snow conditions. Most precipitation gauges suffer from this problem because the orifice must be elevated above ground level with wind being deflected around and over the orifice. Turbulence deflects falling hydrometeors, with the greatest effect being on lighter, slow falling, snow particles. One attempt at solving the undercatch problem is to add shielding to the gauge to reduce the wind speed and turbulence near the gauge orifice and thereby increase the snow that falls into the gauge. While many shields have been developed, there is a practical limit to the size and resulting cost in installing large and expensive wind shields. The size can be a particular problem at airports where most NWS ASOSs are installed. Airports limit the space that is occupied by ASOS and AWPAGs on ASOS are mounted on a rail where the distance between sensors is about ten feet.Over the last three years, the NWS has worked with the AWPAG manufacturer, Ott GMBH, to improve the catch efficiency, by attaching an eight foot diameter Alter style shield to their standard Tretyakov style shield.While this has been proven to significantly improve catch, a longer term objective is to develop a transfer function for the AWPAG with Alter shield. The approach is to install the AWPAG with the new shield near a gauge inside a Double Fence Intercomparison Reference (DFIR) shield, a large wooden structure that is designed to optimize gauge catch to very close to the true catch. The ratio of AWPAG catch to DFIR catch can be correlated to wind speed and possibly other environmental factors to obtain the so-called transfer function (described below). While NWS has installed DFIRs in its testbed at Sterling, VA and its Winter Test Facility in Johnstown, PA, it also needs to collect transfer function data in a region where dry snows accompanied by strong wind are more common than at Sterling or Johnstown. The Government is seeking a contractor and facility which meets this requirement and currently has a gauge inside a DFIR, who has extensive additional precipitation measurement capabilities as well as extensive field test sensor and data acquisition capabilities.Goal:The long term goal of this task is to develop an AWPAG transfer function, a mathematical relationship of the catch ratio of the AWPAG with it's ASOS shield configuration to the catch of a precipitation gauge inside a Double Fence Intercomparison Reference as described in the WMO Report No. 67 (WMO/TD - No. 872,1998) WMO SOLID PRECIPITATION MEASUREMENT INTERCOMPARISON FINAL REPORT by B.E. Goodison and P.Y.T. Louie and D. Yang. Preliminary transfer function development work has been done leading to an equation for the standard ASOS Tretyakov configuration. This is described in the conference preprint paper Development of a Transfer Function for the ASOS All-Weather Precipitation Accumulation Gauge by Jennifer M. Dover presented at 13th Conference on Aviation, Range and Aerospace Meteorology (2008) This equation requires knowledge of the wind speed at orifice height and ambient temperature. The speed can be measured at orifice height, or estimated by an equation that estimates orifice height wind from wind measured at a different height. To adjust gauge measurements for any wind induced bias, wind speed at gauge orifice height during the time of precipitation is required. If the wind is not measured at gauge height, then the station wind speed, which is typically located at 10 m above ground surface, can be used to estimate the wind at gauge orifice height (h) using the following formula:Uh = [log (h/z0) / (log (H/z0))] x UH where: Uh wind speed at the height of the gauge orifice h height (m) of gauge orifice above ground z0 roughness length: 0.01 m for winter and 0.03 m for summer H height (m) of the wind speed measuring instrument above ground, normally 10 m UH wind speed measured at the height H above ground.Then once wind speed at orifice height is measured or estimated, an equation can be used to derive actual precipitation from measured precipitation using the transfer function. As an example, the standard Tretyakov shield transfer function equation for snow is:CR = 103.10 - 8.67 * WS + 0.30 * T Where CR is catch ratio (AWPAG catch/DFIR catch), WS = Wind Speed (m/s) at Gauge Height, and T = Air Temperature (Cº) Since in an automated system there must be a way to determine if the precipitation type is snow, a precipitation identifier such as the one used on ASOS, the Light Emitting Diode Weather Identifier (LEDWI) must be incorporated.Approach:The Government proposes to provide an ASOS AWPAG gauge with the new Tretyakov/ alter shield. This will be installed in the vicinity of the large DFIR. The Government will also provide a LEDWI precipitation identifier. In addition the NWS will provide a standard ASOS anemometer, the Vaisala 425NWS, for installation at 10 meters in the vicinity of the AWPAG gauge. The AWPAG, LEDWI, and 425NWS data will be integrated into the facility's data acquisition system. For the purposes of transfer function development, the contractor will give NWS access to the precipitation measurements from the precipitation gauge that is in the large DFIR. Also NWS will be given access to any data collected that might be necessary or desireable for use in transfer function development. This may include but is not necessarily limited to: • Facility anemometer wind speed and direction at orifice and other heights • Measurements from other precipitation gauges installed in the testbed • Ambient temperature and dew point temperature valuesThis data would be made available by internet (e.g. ftp) so that NWS could download data at least every day. As part of the arrangement, the contractor would have access to NWS AWPAG, LEDWI, and 425NWS data for to their use in any studies that they might wish to conduct. Pre- installation Activities:The Government is pursuing availability of a contractor facility capable of supporting this effort. Contractors who desire to support the task will provide the Government a proposal containing an item by item breakdown of cost to provide the infrastructure and staff to support this effort.NWS would review and determine if funds are available. NWS and the contractor will identify a suitable location for the installation of equipment Installation activities :Install AWPAG, LEDWI, and 425NWS and integrate into facility data acquisition systemContractor provides internet connectivity to permit remote download of data at NWS test facility at Sterling, VA.Post Installation activities:Contractor assist in resolution of problems with gauges such as diagnosis of problems or replacement of failed equipment.At the completion of the evaluation, assist in removal of Government furnished equipment and packing of equipment for return.
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- Place of Performance
- Address: NWS/OST11 1325 East West Hwy SSMC-2 RM 15205, Silver Spring, Maryland, 20910, United States
- Zip Code: 20910
- Zip Code: 20910
- Record
- SN01704417-W 20081115/081113215647-3ee9eef1e97f332f88db857faf0b56b8 (fbodaily.com)
- Source
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