ASOS Ceilometers Sensors

ASOS Ceilometers Sensors 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 Mount Washington Observatory. Request for sole source is to provide continued technical and observation support for study of performance of replacement ASOS ceilometer sensors with particular focus on sensor reporting during periods of subvisible ice crystal layer formation. This study will be conducted during the fall, winter and spring 2008/2009 period for approximately 9 months.This requirement is to field test the ceilometer to demonstrate that it meets the requirements of the ceilometer specification.The vendor is to perform testing to verify that when installed in accordance with vendor specification, the replacement sensor accurately reports cloud heights, and does not falsely report ice crystal layers as clouds in accordance with the contract requirement that under clear sky conditions with surface visibility greater than or equal to 7 statute miles, the sensor shall not report more than three sensor samples as cloud heights during any 30 minute period. Under clear sky conditions (including partial obscurations) with surface visibility greater - mile less than 7 miles, the sensor shall not report more than five. These criteria shall be met during both daylight and night conditions which persist for at least one hour. Of particular interest is the accuracy of the cloud height reports when the sensors are tilted at various angles to vertical, ranging from 0 degrees to approximately 5 degrees.The vendor is to accomplish testing at an extreme and severe winter weather location capable of providing appropriate sensor mounting space and clinical human observations to include availability of reference standards to verify human observations. The vendor will also be responsible for investigation of anomalous reports. This is not a request for competitive proposals. However, interested companies may submit an affirmative response to the requirement within ten (10) days from the posting date of this notice to Joyce.Dickerson@noaa.gov or fax 301-713-1024. A determination by the government not to compete this proposed contract based upon responses to this notice is solely with the discretion of the government. No telephone requests will be honored. Award will be made under commercial simplified acquisition procedures, FAR Subpart 12.ASOS Ceilometers Sensors Statement of Work Statement of Work For continued testing to determine performance of the Vaisala CL31 ASOS ceilometer in severe winter environment at Mount Washington Observatory 1.0) Background:1.1) The Automated Surface Observing System (ASOS) is the primary observing system for the National Weather Service. ASOS is configured to provide a complete automated aviation observation in support of flight operations at over 1000 airports throughout the U.S. including Hawaii and Alaska. A key element of the surface aviation observations (METARs and SPECIs) is sky condition, which is provided automatically by a ceilometer which measures cloud height overhead, and then uses 30 minutes of cloud measurements to produce a sky condition report similar to that provided by a manual observer. 1.2) The current ceilometer that is installed on ASOS is out of production and must be replaced. After competitive procurement, a contract has been awarded to Vaisala, Inc. to replace the current ceilometer, which measures clouds to 12,000 feet with a modified commercial model CL31 ceilometer capable of measuring to 25,000 feet. The designation for this sensor is CL31 ASOS. As part of this procurement, the Government is responsible for compliance and field testing the ceilometer to demonstrate that its meets the requirements of the contract specification when installed in harsh winter locations.2.0 Goal:2.1) The overall goal is to evaluate the performance of the ceilometer during severe winter weather events. A specific area of concern is its detection and false reporting of subvisible ice crystal layers as clouds. The reporting of these layers as clouds has caused widespread criticism of the automated sky condition at locations where these subvisible clouds are likely to occur below 12,000 feet. Specifically these locations are in the northern tier of the U.S. and Alaska. Obviously with the introduction of ceilometers measuring to 25,000 feet, the likelihood of detecting these ice crystal layers will increase. To address this problem, the ceilometer contract specifically requires the vendor to propose strategies to prevent these subvisible ice crystal layers from being reported as clouds. The Government will be responsible for conducting a field test to assist the vendor in this effort and to provide high resolution data to specifically assist the vendor in analyzing the ceilometer backscatter profile to understand the nature of these subvisible layers. This will provide the vendor data to characterize these ice crystal layers and develop internal processing schemes to prevent them from being reported as visible clouds. The Government desires to evaluate the reporting accuracy of the CL31 ASOS during severe winter events to include frozen precipitation, fog, and high wind events.3.0 Approach:3.1) Vaisala has proposed tilting the ceilometer 12 from vertical to eliminate false ice cloud layer reports. Testing during Winter 2007/2008 demonstrated that this aggressive angle causes compliance issues. The NWS proposes a tile angle of 2-5 - degrees from vertical. This proposal is to install two CL31 ASOS 25,000 foot ceilometers at a location likely to experience subvisible ice crystal layers. One ceilometer would be tilted 2-5 and the other would be vertical. An older 12,000 foot ceilometer might be included to compare relative performance in ice crystal conditions3.2) The Government is tasked with identifying one or more locations where the test could be conducted, and to develop the necessary data collection system to acquire the data that will be required to support the post analysis that Vaisala will conduct to solve the problem. The Government seeks a location at over 6000 feet above sea level, and infrastructure to support scientific investigations. A key capability is a dedicated observing staff that could be tasked with checking the ceilometer to see if is detecting subvisible clouds and documenting the conditions under which it occurs. Extensive webcam views should also be available at the facility to assist in evaluating conditions.4.0 Pre- installation Activities:4.1) The selected site will provide the Government a proposal with item by item breakdown of cost to provide the infrastructure and staff to support this effort.4.2) The selected site will Identify a suitable location for the installation of equipment and data collection systems.5.0 Installation activities :5.1) Site personnel will prepare appropriate installation mounting fixtures adequate to reduce instrument vibration. If appropriate, site personnel will build appropriate shelters around the ceilometers to help shield them from gusty winds and lateral icing 5.2) Site personnel will assist with installation of ceilometers and associated data acquisition systems and connect to the internet. 5.2) Provide guidance to observation staff on observation procedures to identify and document the occurrence of false cloud layers caused by subvisible ice crystal layers.6.0 Post Installation activities:6.1) Provide supporting observations thorough a period of approximately 10 months, beginning in early winter 2008 and continuing through late Spring 2009. The Government anticipates some periods during winter icing season when sensors would be iced over and test would be suspended until the ice cleared.6.2) Provide internet connectivity to permit remote download of data at NWS test facility at Sterling, VA.6.3) Monitor DAS for outages, and ceilometers for ice blockage, conditions permitting.6.4) If the site is forecasted to be in the clouds for a long period, or if heavy icing is forecasted, cover the ceilometers if appropriate.6.5) At completion of the testing, site personnel will assist Government personnel in dismantling all Government provided equipment and preparing the equipment for shipment.7.0 Government Furnished Equipment:a) Two (2) ceilometers with necessary cabling; b) One (1) Data Acquisition System; c) Documentation containing the observational procedures necessary to determine the presence of false cloud layers.