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An Intercalibration and Quality Assurance Program using a Stand-Alone Wireless IMET System

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July 1, 2004 through June 30, 2005

Mr. David Hosom
Woods Hole Oceanographic Institution, Woods Hole, MA 02543

Program Manager: Dr. Sidney W. Thurston, NOAA/CPO/OCO

Related NOAA Strategic Plan Goal:
Goal 2. Understand climate variability and change to enhance society’s ability to plan and respond.

The Nation is entering a new era of climate research and prediction requiring a major expansion of capabilities for climate observations over the oceans. Improved observations are needed for operational forecast centers, international research programs, and major scientific climate assessments. Air-sea interaction plays a significant role in this problem and, as time scales increase from weeks, to intra-seasonal, to seasonal, the importance of air-sea interaction increases.

This project is directed at the development of a system to ensure that shipboard observations of the air-sea fluxes are of the highest quality, as needed by research programs such as CLIVAR and SOLAS, and as needed so that the shipboard systems can provide in-situ calibrations of the ocean observatories under development by NSF. The goal of the project is to improve the quality and quantify the accuracy of shipboard meteorological and air-sea flux observations to the point that the data will meet the requirements of the science programs and provide the means to do in situ calibrations of the time series stations that will be maintained by some of these same ships. Future proposals will address the fabrication and engineering test of the system.

It is a challenging task to instrument a ship to do high quality meteorological and air-sea flux observations. Placement of the sensors is critical. Distortion of the flow, shadows, heat, soot, radio frequency emissions, and spray effects must be minimized, but at the same time the sensors must be accessible. For each sensor, the issues are different; and while computation of the flow around the ship helps locate optimum locations, to date an empirical approach has proven to be most useful. Further, there needs to be a standard or reference set of observations to be used to judge the success of the trials to identify best locations. A recent workshop on high-resolution marine meteorological measurements (Smith, et al. 2003) discussed the problem and identified three important issues: (1) the need to have a data quality assurance program to firmly establish that meet the observations accuracy requirements, (2) a need for observations at high time resolution (about 1 minute), and (3) a need to more efficiently utilize research vessels including realizing their potential for the highest quality data and their potential to provide more
direct and more comprehensive observations.

At present, observations from scientific research vessels have well-documented problems and may not be routinely recorded when the vessel is at sea; and because of accuracy limitations, many VOS data require cumbersome correction procedures and are still not useful in some applications. To address these problems, it is proposed to construct a transportable instrument suite to provide a standard for evaluating and improving ship-based observations of variables used in near-surface bulk meteorology and fluxes. The “roving standard” would be installed on the NOAA ship Ron Brown as an engineering test. After successful test and evaluation, and using NOAA-OGP funding for operational use, this ‘roving standard’ will be deployed on UNOLS (NSF and Navy) and NOAA research vessels in a sequence of studies of each vessel.

• The sampling concept for the HRSAW is for the Central Controller to collect one minute data from all modules each one (or more) hours and relay that data to the bridge or science lab on the ship for processing, merging with data from the ship’s standard sensors for comparison purposes. Obtaining 60 (or more) one-minute values as a block permits the radio modem to duty cycle for reduced power. The bridge would use a radio modem and Bridge Computer (PC) operating on ship power. The Central Controller and all of the HRSAW modules would be battery powered for up to a month at a time. The inside-hull-mounted SST (sea surface temperature) system would use the HullCom acoustic modem from the AutoIMET system used on VOS so that cabling is not required. The SST would record one minute data internally but only send averaged data to the deck every 15 minutes or so. The following figure shows the module configuration.

The following Task List has the status comments in bold print.

1. Develop the HRSAW “kit” including the mechanical configuration and PC board layout and firmware. Purchase a custom battery for the unit. Prototype a unit for test and evaluation. The mechanical configuration is complete. The PC boards are in work.

2. Modify existing ASIMET firmware to store several hours of one minute data and create a new command for access to this data. Evaluate the existing memory board for improved operation including data extraction. The PCMCIA memory card can now be replaced by a standard Compact Flash Card for lower cost and greatly increased storage capability.  The new module controller PC card is in work that will use the CF and will have improved low temperature operation. The firmware for this card is in work and will address the HRSAW requirement for data retrieval via wireless connection to the bridge.

3. Design and prototype a mounting-bracket system that is easy to install and use. This mounting system is in work and is similar to the VOS brackets now in use.

4. Design the Central Controller including packaging, PC board layout and firmware. Prototype a unit for test and evaluation. Work on this task is not started.

5. Purchase and design the Bridge Computer System for test and evaluation. The bridge computer is being purchased in preparation for system design.

These tasks complete the design phase of the program. The following tasks will be proposed for future funding from multiple agencies. This will result in a research ship and VOS, portable calibration system for the climate community.

1. Purchase commercial ASIMET modules and parts for HRSAW “kits”.
2. Plan the CFD modeling for the Oceanus and Ron Brown in cooperation with SOC.
3. Complete fabrication and testing of system components.
4. Initial calibration for all modules.
5. System integration and burn-in at WHOI.
6. Installation and test of key system components on the R/V Ron Brown for coordinated engineering evaluation of components and system and will be performed dockside.
7. Upgrade and modify as required based on engineering evaluation.
8. SOC will complete the CFD for the Oceanus testing.
9. Install on WHOI ship for short test cruise. (Probably the R/V O

Last updated: August 19, 2008

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