An international long-term collaboration to study the climatic and environmental feedback mechanisms involved in the African monsoon, and in some of its consequences on society and human health. The programme, which started in 2004, has developed a network of ground-based observation stations over Sub-Saharan West Africa to measure heat flux and, for some stations, CO2 and H2O vapour fluxes. Files also include concomitant meteorological measurements (wind, temperature, pressure, humidity, rainfall) and soil physics parameters (soil temperature and moisture). The UK branch of AMMA makes use of several instruments provided by the UK Universities Facility for Atmospheric Measurement (UFAM) which are centred on the Niamey meso-site. The Facility for Airbourne Atmospheric Measurements (FAAM) aircraft was used during the July-August 2006 campaign.

The ship based SYNOP messages measurements describe hourly observations from sea based stations (ships, rigs, platforms and moored buoys) distributed globally. The observations cumulate in around 10,000 reports a day, giving measurements of parameters such as wind speed and direction, maximum and minimum air temperature, sunshine duration, rainfall accumulation, and cloud type. The data are collected by observation stations worldwide and transmitted within the ship SYNOP message.

The land based SYNOP messages measurements describe hourly observations from land stations distributed globally. The observations cumulate in around 60,000 reports a day, giving measurements of parameters such as wind speed and direction, maximum and minimum air temperature, sunshine duration, rainfall accumulation, and cloud type. The data are collected by observation stations worldwide and transmitted within the land SYNOP message. Data are extracted from the Met Office's MetDB system before being sent to CEDA for archiving. These extractions occur at the 4 principal synoptic periods (00-06, 06-12, 12-18 and 18-00 UT). The dataset contains a range of measurements including: - Wind speed and wind direction - Maximum and minimum air and grass temperature - Horizontal and vertical visibility - Snow depth - Dew-point temperature - Relative humidity - 3 -hour pressure change - Height and period of wind waves - Cloud height and type - Radiation in last 24 hours - Maximum gust period - Past and present weather - Rainfall accumulation - Precipitation amount - Sunshine duration The wind speed and vertical gust speed are given to the nearest metre per second, and the vertical gust acceleration to the nearest metre per second squared. The wind direction from which the wind blows is measured in Degrees (true). The entry for an east wind is 090, for a south wind it is 180 and so on clockwise. Note that zero values in both wind speed and wind direction fields indicate that there was no wind blowing at the time of observation. The air temperature, grass temperature and dew-point temperature are measured in Kelvin. The cloud height, visibility, snow depth, and wind-wave height are given in metres. Sunshine duration is recorded over 24 hours and over one hour. For the former, the measurement is in hours, but for the latter the measurement is in minutes. The past weather is recorded as a number between 0-9 which details what the weather has been like in the last 6 hours for observations at 00, 06, 12, 1800 UTC, the last 3 hours for observations at 03, 09, 15, 2100 UTC and the previous hour at any other times. The past weather is only recorded when a manual observation is done at the station. The relative humidity is measured as a percentage. Documentation and Links to further information and references (see linked documentation on this record): Some general information about surface station readings can be obtained from the abridged version of "MIDAS Data Users Guide", provided by the Met Office. This document describes the meteorological surface data in the Met Office Database - MIDAS. This guide is rich in information and is aimed at those with little familiarity with observing methods or instrumentation. Details of the WMO Meteorological codes used at weather observing stations (daily and hourly weather) explain the codes used in this dataset further.

The Met Office European synoptic stations reported hourly surface data from 141 European stations for the period 1990-1996. Parameters for this dataset include: present and past weather, cloud amount, type and base height, wind direction and speed, visibility, temperature measurements, water vapour pressure, relative humidity, mean sea level pressure, rainfall and gust speed and direction. Note - this has been superseded by the MIDAS Land Surface Station Dataset. Additional background information can be found at the Monthly Weather Report: Vol. 108, 1991, ref. UDC 551 506 1(41-1) , produced by the Met Office.

The Met Office European synoptic stations reported hourly surface data from 141 European stations for the period 1990-1996. The dataset includes parameters such as temperature, wind, rainfall, cloud cover, past and present weather, and visibility. Note - this has been superseded by the MIDAS Land Surface Station Dataset.

The global radiation observation data contain hourly and daily radiation amounts, including those no longer being reported. The measurements of global solar irradiation amount, diffuse solar irradiation amount, direct irradiation amount, irradiation balance amount, and global horizontal illumination are recorded by observation stations worldwide and transmitted within SYNOP, HCM, AWSHRLY, MODLERAD, ESAWRADT and DRADR35 messages. The data span from 1947 to present.

Observational data extracted from the Met Office's MetDB system. Data include surface and upper air observations and some satellite data. These data are from a number of different message types covering data from land and ship surface data measurements through to upper air observations from wind profilers, radiosonde ascents and aircraft measurements and also satellite measurements. Data arrive at the Met Office as per standard messages transmitted from source (e.g. SYNOP, METARS, TEMP message types) and are then decoded within the MetDB system. CEDA receives a text output from the MetDB system of these deciphered messages which are then processed into the BADC-CSV format where possible. Messages are split up by observation date at this stage. METARS and CLIMAT data are not decoded by the Met Office and are stored as per the original message. Details about the contents of each message type are given in the links in the 'online resources' section of this record. "Raw" data for all message types are available through the /raw folder within the archive. Each raw file contains messages received within a given period of time at the Met Office and are not sorted by observation date.