Met Research Unit, Cardington
Instrumentation Facility

Met Office home page

By: James McGregor

BADC - Cardington page


NB: The inclusion in this document of the name of a company does not constitute any endorsement or recommendation by the Met Office of that company's products or services.

1. Introduction

The Met Research Unit, located at Cardington in Bedfordshire (52o 06' N, 00o 25' W, 29m amsl), maintains a suite of surface-based and mast-mounted instrumentation. The main purpose of this instrumentation site, which is logged 24 hours a day, is to provide data for atmospheric processes research, and for the testing and validation of numerical model output and performance.

The Cardington site has an open fetch in all directions, with the exception of to the north, where the presence of two large airship hangars have a major influence on the air flow. Measurements of turbulence therefore, when the wind is coming from a direction of roughly 355o to 035o, should be treated with caution.

Cardington Hangars
Cardington airship hangars (with instrumented 10m mast in foreground)

2. Instrumentation

This section outlines the instrumentation deployed on the site. More detailed technical descriptions of some of the instruments are available by clicking on the links.

2.1 Wind and turbulence measurement

25m mast instrumentation
Ultrasonic anemometer mounted at the top of the 25m mast. (Also present: temperature and humidity sensors inside aspirated screens)

2.2 Temperature measurement

2.3 Humidity measurement

Sonic anemometer and Licor mounted on 10m mast
This picture shows the LI-COR LI-7500 gas analyser co-located with a sonic anemometer, on the 10m tower.

2.4 Radiation measurement

The surface site consists of a full suite of radiometers, measuring all the main components of the radiation budget:-
Kipp & Zonen Solar Tracker Infrared thermometer and CG4 pyrgeometer
Above: Radiometers mounted on a Kipp & Zonen solar tracker.

Right: Downward-facing pyrgeometer at end of boom, and Heitronics IRT pointing at the ground.

2.5 Visibility & aerosol measurements

2.6 Sub-soil sensors

A number of sub-soil sensors are deployed. These sensors are situated at two different locations in the Cardington field site (designated the "west" site and the "south" site.):-

2.7 Miscellaneous sensors

3. Data Logging

The overall structure of the logging system is illustrated in this schematic diagram.

The three sonic anemometers are logged at a rate of 10Hz on a PC running windows XP, using software developed in-house. The other sensors that are mounted on the 10,25 and 50m masts are connected to the analogue inputs of the anemometers and are logged in the same data streams. Data from the 25m and 50m sonics is transmitted to the logging PC, via pairs of radio modems.

All the remaining sensors are logged using three commercially available dataTaker ( DT800 loggers. The loggers use a raw sampling rate of 0.5 Hz, and one minute averaged data is logged. Another PC running windows XP interrogates these loggers at regular intervals, and downloads the data from them.

4. Data Processing

The data processing routines output three files per day. These contain data averaged over time periods of 1 minute, 10 minutes and 30 minutes. Turbulence quantities and data from slow response sensors are included in the 10 minute and 30 minute datasets only. A full description of the data format, and a list of parameters, can be found here.

Last Modified:- 6th November 2006