SON-145022-24-0037.pdf

Statement of Need 145022-23-0037

1. Background and Purpose The Air Resources Laboratory (ARL) Atmospheric Turbulence and Diffusion Division (ATDD) of NOAA seeks to purchase various MetOne instruments for use in the United States Climate Reference Network (USCRN). This research facility worked with the manufacturer to provide this customized product for our highly accurate research measurements. As part of the overall research objectives, the United States Climate Reference Network (USCRN) has used fan aspirated shields for nearly two decades.

This research facility strives to maintain consistency with equipment such as to allow easy intercomparison between measurements across various field campaigns (whether short or long-term).

2. Scope and Objectives

The U.S. Climate Reference Network (USCRN) is a network of climate stations developed as part of a NOAA initiative. Its primary goal is to provide future long-term homogeneous observations of temperature and precipitation that can be coupled to long-term historical observations for the detection and attribution of present and future climate change. Data from the USCRN will be used in operational climate monitoring activities and for placing current climate anomalies into a historical perspective. The USCRN also provides the United States with a reference network that meets the requirements of the Global Climate Observing System (GCOS). The USCRN presently consists of 140 stations installed and maintained since 2000 throughout the continental United States, Alaska, Hawaii, and an experimental site in Canada. New site installations are expected to continue in Alaska for the next several years. The primary measurements of USCRN are air temperature and precipitation. Soil moisture and soil temperature are also primary measurements for sites in the contiguous US (i.e., CONUS). Auxiliary measurements are solar radiation, ground surface temperature, wind speed, and relative humidity.

The scientific equipment used for USCRN climate monitoring stations was chosen after thorough market evaluation and comparison by an expert scientific panel as outlined in the USCRN program directives. NOAA’s existing Climate Reference Network’s historical success is proven by the 99% data ingest rate and 98% dataset completeness. All changes to the network must be approved by the panel only after extensive testing and evaluation, plus a two-year evaluation period. Leveraging off the success of hardware and equipment selected and implemented in the USCRN allows for easy transferability of calibration standards for both temperature and precipitation, and system maintenance protocols and procedures. The current baseline instrument configuration consists of a Campbell Scientific CR3000 datalogger, Geonor rain gauge with 3 vibrating wires three, Met One Instruments fan aspirated radiation shields, 3 platinum resistance thermometers, and a Vaisala wetness (rain detector) sensor.

These stations are intended to run for at least 50 years. It is important that the instrumentation, where possible, be standardized across a network. This allows the quality control / quality assurance processes, maintenance procedures, mounting hardware, etc., to be standardized. Any significant changes in instrumentation would require an extensive test and two evaluation period, along with rewriting of all associated software and introducing unwanted measurement errors that could be interpreted as a false climate signal.

All of the USCRN stations currently have either two (PN 076B-7398) or three (PN 076B-7308) Met One fan aspirated radiation shields that house the air temperature and relative humidity sensors. PN 7399 is the required cable for PN 076B-7398, and PN 7323 is the required cable for PN 076B-7308. These aspirated radiation shields contain fans that pull ambient air through the shields at an optimum rate for obtaining accurate air temperature and relative humidity measurements. All of these items are custom versions for NOAA of the standard model 076B aspirated shield manufactured by Met One.

Another item in the USCRN instrumentation suite at every USCRN station is a Met One model 014A anemometer that is used to measure wind speed. USCRN protocol requires that the bearings (two per anemometer) be replaced as a part of the annual maintenance procedure.

The requested items with PN 076B-7398 and PN 7399 are direct replacements for the fan aspirated radiation shields currently deployed in the USCRN network. USCRN protocol requires that the aspirated shields be replaced if faulty or damaged.

The requested items with PN 1898 are direct replacements for the bearings in the Met One 014A cup anemometers currently deployed in the USCRN network. USCRN protocol requires that the anemometers be replaced if faulty or damaged.

Based on extensive market research and decisions made by the USCRN Scientific Review panel, the Government has determined that the model 076B fan aspirated radiation shields and associated cables, and the anemometer bearings manufactured by Met One, are the only products commercially available that fulfills the requirements above and that are compatible with the existing receiving systems owned by

NOAA/ARL/ATDD.

3. Product’s Technical Specifications

● Radiation errors independent of outside emissivity

● Corrosion free

● Durable, reflective coating

● 12VDC power

● Triple radiation shielding

● Aspirating fan

● Internal sensor mounting compatible with ½" or ¼" sensor bodies

● -50 to 85 deg C temperature range

● 1" pipe mount and easily serviceable

Part Number Description Qty

1889 bearings 300

2844 Switch reed for anemometer 014A 30

7323 DC POWER CABLE ASSEMBLY,

076B-7308, 12 M / 40

076B-7308 NOAA RADIATION SHIELD, FAN

ASPIRATED, 12VDC (TACH)

4. Ship to Address:

NOAA/ARL/ATDD

Attn: Dr. Temple Lee - USCRN Program 456 S. Illinois Ave.

Oak Ridge, TN 37831