Leaf Area Index (LAI) measurements were collected using a Delta-T SunScan as part of the Network for Calibration and Validation of Earth Observation data (NCAVEO) 2006 Field Campaign. Data were collected from the following experiment fields: Rickyard (winter wheat), Fairpiece (winter oats) and Brockley (spring barley). The parameters required by the SunData program were set as follows: • Leaf Angle Distribution Parameter = 1.0 • Leaf Absorption Parameter = 0.85 Five sample points were located within tramlines in each field and their position determined using dGPS. Five 10 metre long transects were set-up, centred on each of these points and marked with coloured flags, marking the longitudinal extent of each Elementary Sampling Unit (ESU). The ‘width’ of the area sampled within the crop was determined by the reach of the instrument, around 1 metre. The geographic co-ordinates in the data file have been calculated to allow for the offset of sample measurements from the tramlines, and these should be taken as the definitive locations of the individual samples. SunScan measurements were made every metre along a 30 m transect, the central 10 m length of which coincided with the area between the coloured flags. Each of the extended ESUs was sampled in the same order in each field: Red, Green, Blue, Yellow, White flag, following a path along the tramlines shown in Figure 1. This gave a total of 165 LAI measurements per field. The geographic co-ordinates of each measurement were recorded and represented alongside the measured variables. For further details see the dataset's metadata document in linked documentation.

The European Arctic Stratospheric Ozone Experiment is a European Commission (EC) measurement campaign undertaken in the Northern Hemisphere winter of 1991-92 to study ozone chemistry and dynamics. The dataset contains measurements of chemical constituents (concentrations of ozone and the members of the chlorine and nitrogen families) and meteorological parameters from European ground stations and balloon and aircraft flights, and from the ground-based ozone monitoring network. This dataset is public. This dataset was produced using a Nd-YAG laser, 0.6m diameter mirror, two receiver channels - one for parallel and the other for perpendicular polarisation. Photon counting system; raw data collected at 30m resolution (both channels simultaneously). Each individual measurement takes 5 minutes (5000 shots). For the data here, all measurements for an individual evening have been combined. Usually, 2 or 3 consecutive runs were made, but on some evenings (e.g. December 6-9 1991) a large number of profiles were measured. Times of measurements are not given here but can be supplied on request; each was made within 4 hours of 2000 GMT and during hours of darkness. Detailed data for each run are also available on request. To derive backscatter ratios, atmospheric density profiles were derived from ozonesondes launched from Aberystwyth during EASOE. These were corrected for air and ozone absorption. The top of the aerosol layer for each night was determined by inspection of the counts*height squared (Ch2) profile, and the average ratio of Ch2 to corrected density above this height was used to derive the backscatter ratio. Correction for aerosol absorption was made using an extinction/backscatter ratio of 40, assumed constant throughout the layer. For depolarisation ratio, the ratio of the two receiver channels is shown, corrected for the beamsplitter efficiency. Also, all the data have been normalised so that the lidar depolarisation ratio for air (above the aerosol layer) is 1.4%. (Note: this is different from the preliminary data). Data are shown above 10 km, except where cirrus was present, when the altitudes contaminated by cirrus have been removed. Below 10 km, the count-rates were too high for the recorded data to be reliable. The upper height reported is that of the top of the aerosol layer.

The Atmospheric Chemistry Studies in the Oceanic Environment (ACSOE) was a 5-year Natural Environment Research Council (NERC) programme on tropospheric chemistry coordinated by the University of East Anglia and involving research groups from a number of UK universities and research institutes. The project had three consortia of UK institutes and universities, each of which focused on a different scientific topic. OXICOA (OXIdising Capacity of the Ocean Atmosphere) was a study of oxidant, radical and related gas-phase chemistry in the clean and moderately polluted marine atmosphere. The Testing Atmospheric Chemistry in Anticyclone (TACIA) project as part of the ACSOE-OXICOA program was carried to collect data. The dataset was collected by the C-130 research aircraft; a former transport aircraft operated by the Meteorological Research Flight (MRF), and includes in situ trace gas photochemistry measurements.

The overall aim of the UK Surface Ocean / Lower Atmosphere Study (UK SOLAS) is to advance understanding of environmentally significant interactions between the atmosphere and ocean, focusing on material exchanges that involve ocean productivity, atmospheric composition and climate. The knowledge obtained will improve the predictability of climate change and give insights into the distribution and fate of persistent pollutants. The dataset contains biological and chemical measurements such as: major nutrients and trace metal concentrations in aerosol and rain samples, chemical analyses of inorganic micro-nutrients, dissolved and particulate trace metal and carbon analyses, dissolved nitrogen and organic phosphate, biological measurements including phytoplankton pigments, bacteria, picoplankton and larger phytoplankton abundance.

Sunphotometer data was collected on 17th June 2006 using three identical Microtops II instruments, as part of the Network for Calibration and Validation of Earth Observation data (NCAVEO) 2006 field experiment. The instruments were operated at three locations near Chilbolton: the roof of Chilbolton Facility for Atmospheric and Radio Research's (CFARR) main building, the Hampshire Golf Club and Cowdown Farm. On using the three instruments together on the roof of the CFARR main building, results showed differences between the three instruments, with data from s/n 8407 being closest to that measured by the Cimel sunphotometer at the same location. Note that the date of s/n 8407 was set incorrectly to 2005, but has been corrected in the NASA Ames formatted file. This should not affect the data collected. The same instrument also did not record the water vapour amount, so this is shown as -999.0 in the data file. On the ‘golden day’, 17th June 2006, measurements were made with all three instruments every five minutes between 09:30 and 11:30 GMT. Sporadic measurements were also made at earlier and later times. The s/n 8407 did not make a reading at 11.15 as anticipated. A large number of parameters and calibration constants were used to achieve these readings and are included alongside the main data. For further information please refer to the Microtops II User’s Guide.

Data were collected on 6th January 2009 by the University of Manchester GRIMM dust monitor at the Chilbolton Observatory, Hampshire, in support of the FAAM campaign in the South-West of the UK. The dataset contains measurements of aerosol concentrations. The data were collected for use in the CLOUDS project, which is one of multiple projects within the APPRAISE (Aerosol Properties, PRocesses And Influences on the Earth's climate) programme.

This dataset contains ozone, NO, NO2, NOX, SO2 and PM2.5 air quality and meteorological measurements from two campaigns undertaken in Guangzhou, China in 2019. NO, NO2 and NOX were measured by Chemiluminescence with a Thermo scientific 42i-TL. Ozone were measured via UV with a Thermo scientific 49i. PM2.5 were measured by a continuous particulate monitor (BAM-1020, Met One instruments Inc). SO2 were measured via Pulsed fluorescence with a Thermo scientific 43i-TLE. This data were collected as part of the NERC project Investigating the large source of particulate mass from nitrophenols observed in Beijing during winter haze events (NITRO-PM).

This dataset contains spectral radiometer j(O1D) measurements. Oxidant and Particle Photochemical Processes above a South-East Asian tropical rain forest (OP3-Danum-08) is a 3-year Consortium Grant of the Natural Environment Research Council (NERC), beginning 1 October 2007. The objectives of the OP3 project are (i) to understand how emissions of reactive trace gases from a tropical rain forest mediate the production and processing of oxidants and particles in the troposphere, and (ii) to better understand the impact of these processes on local, regional and global scale atmospheric composition, chemistry and climate.

This dataset contains spectral radiometer j(NO2) measurements. Oxidant and Particle Photochemical Processes above a South-East Asian tropical rain forest (OP3-Danum-08) is a 3-year Consortium Grant of the Natural Environment Research Council (NERC), beginning 1 October 2007. The objectives of the OP3 project are (i) to understand how emissions of reactive trace gases from a tropical rain forest mediate the production and processing of oxidants and particles in the troposphere, and (ii) to better understand the impact of these processes on local, regional and global scale atmospheric composition, chemistry and climate.

The Network for Calibration and Validation of EO data (NCAVEO) ground data collection programme included a series of transects on the River Test at Chilbolton Cow Common, an area of semi-natural wet grassland. The river survey was carried out on the 16th June between 11:15 and 13:15 at site Chilbolton 1 and 15:30-17:00 at Chilbolton 2, the day before the ‘golden day’ on which the airborne data were collected by the Environment Agency / Natural Environment Research Council (NERC). The sampling strategy used was based on the desire to capture; (1) data over the range of water depths, (2) a dense and extensive sample of data to allow for bathymetric modelling of the river regions and (3) data over a broad range of substrate types to represent all varieties within the study region (e.g. from marginal vegetation to silts and to gravels). The variables recorded included: Easting; Northing; Water depth (cm); Depth to bed (cm); Surface velocity (m/s); Dominant substrate. Surface velocity was measured using a Valeport uni-directional electro-magnetic current meter (Valeport Ltd.). For more information on the collection and processing of the data please see the dataset's metadata document, in linked documentation. A video of David Spear describing the survey is available also included in the directory.