Ground based and airborne in-situ aerosol measurements during the APPRAISE-CLOUDS (Aerosol cloud interactions and climate) project from the Chilbolton Atmospheric Observatory, Hampshire (South West England) and on board the FAAM BAE-146 research aircraft. 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. Airborne measurements for the APPRAISE-CLOUDS project were also carried out using the FAAM BAe146 aircraft. In total 20 flights were carried out as part of this project with the aircraft operating from Cranfield, Exeter and Oberpffafenhofen, Germany. For the APPRAISE-CLOUDS project the aircraft was equipped with a range of cloud and aerosol instruments including FSSP (cloud droplets), CPI (ice particles), 2DS (ice particles), 2DC (ice particles), 2DP (ice particles), CAPS (droplets, ice, large aerosol), AMS (aerosol chemistry), SP2 (soot aerosol), PCASP (aerosol size), SMPS (aerosol size), Filters (aerosol chemistry), CVI (cloud particle residuals), Nephalometers (aerosol scattering), PSAP (soot aerosol), Whole Air Samplers (trace gases - post flight analysis), Trace gas analysers (NOx, O3, SO2). Missions typically involved flight legs above and below cloud to characterise aerosol in the vicinity of the clouds, and flight legs within cloud to characterise cloud properties and attempt to measure cloud particle residuals. In total 110 flight hours were allocated to this project. Flight No. Date Location B331 6/12/07 SW England B336 8/01/08 SW England B337 15/01/08 SW England B338 17/01/08 SW England B376 15/05/08 SW Germany B377 17/05/08 Switzerland B378 18/05/08 Switzerland B421 17/12/08 Cardigan Bay B422 15/01/09 SW England B423 20/01/09 Bristol Channel B424 21/01/09 SW England B425 22/01/09 SW England B426 28/01/09 SW England B430 18/02/09 SW England B431 26/02/09 SW England B432 27/02/09 Scotland B433 3/03/09 SW England B434 3/03/09 SW England B449 27/05/09 SW England B456 6/06/09 SW England

This dataset collection contains cloud products produced by the Cloud project within the ESA Climate Change Initiative (CCI). The ultimate objective of the ESA Cloud Climate Change Initiative (Cloud_cci) project is to provide long-term coherent cloud property datasets exploiting the synergic capabilities of different Earth observation missions allowing for improved accuracies and enhanced temporal and spatial sampling better than those provided by the single sources. CC4CL (Community Cloud Retrieval for Climate) and FAME-C (Freie Universität Berlin AATSR MERIS Cloud) are optimal estimation based retrieval systems providing GCOS cloud property Essential Climate Variables (ECVs) including uncertainty estimates. These global datasets contain cloud fraction, cloud top level estimates (pressure, height, and temperature), cloud thermodynamic phase, spectral cloud albedo, cloud effective radius, cloud optical thickness as well as cloud liquid and ice water content. The AATSR-MODIS-AVHRR heritage product family obtained by CC4CL is based on measurements from ATSR-2/ERS-2, AATSR/ENVISAT, MODIS/AQUA, MODIS/TERRA, and AVHRR on-board NOAA-7, 9, 11, 12, 14, 15,16, 17, 18,19, and MetOp-A. The second product family contains cloud properties derived from ENVISAT’s AATSR and MERIS observations using the synergetic retrieval system FAME-C. In the first phase (2010 – 2013) of the Cloud_cci project prototype retrieval versions have been established leading to preliminary results covering 2007, 2008, and 2009, herein referred to as demonstrator datasets. In Phase 2 (2014 – 2016) both retrieval schemes have been substantially improved enhancing the data quality of the cloud products spanning the time period from Jan 1st 1982 to Dec 31st 2014. Considerations for climate applications: Due to the short period (i.e. 3 years) of the current available demonstrator datasets, it is not possible to perform long-term data comparisons or to support long-term climate analysis. Please be aware of the fact that by the end of 2016 at the latest these prototype datasets will be replaced by the complete multi-decadal Cloud_cci climatology (1982 – 2014) together with updated Product User Guide (PUG) and Product Validation and Intercomparison Report (PVIR) documents. We would like to stress that one of the main objectives in the second phase of the Cloud_cci project has been the further development and improvement of both retrieval schemes and their processing systems. As a consequence, the quality and accuracy of the final cloud products have been considerably improved compared to the currently available demonstrator datasets.

The Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) was a joint-mission between NASA and the French space agency Centre National d'Etudes Spatiales. The main objectives of the mission was to supply unique data set of vertical cloud and aerosol profiles. This dataset contains cloud and aerosol lidar level 2 1km cloud layer version 3-30 data product, which provides cloud data derived from Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) Level 1B product at 1 km horizontal resolution, with full complement of diagnostic and quality assurance parameters. The data provides range of parameters including vertical profile of cloud layers, optical depth. Version 3-30 was released in April, 2013. This version incorporates two ancillary input files updated from those used in versions 3-01 and 3-02: GEOS-5 processing system version 5.9.1 from version 5.2; and the enhanced Air Force Weather Authority (AFWA) Snow and Ice Datasets. The resulting changes are relatively small.

This dataset contains point measurement of snow-air transition temperatures at 2 cm intervals on a 5 m thermistor chain installed spanning the snow-air transition at Summit Station, Greenland. Measurements were made using a Snow Ice Mass Balance Apparatus (SIMBA) with a bespoke 5 m chain. These data were collected as part of the joint Natural Environmental Research Council (NERC) and US National Science Foundation (NSF) -funded Integrated Characterisation of Energy, Clouds, Atmospheric state, and Precipitation at Summit - Aerosol Cloud Experiment (ICECAPS-ACE) project. These data were continued through the 3 year extension to the ICECAPS-ACE project called ICECAPS-MELT.

This dataset contains near-surface wind profile from four sonic anemometers distributed on the 15 m tower at Summit Station, Greenland, detected by Lufft VentusX, heated 2D sonic anemometer, and Metek uSonic-3 scientific, heated 3D sonic anemometer. Data are 1 minute averages concatenated into monthly files. These data were collected as part of the joint Natural Environmental Research Council (NERC) and US National Science Foundation (NSF) -funded Integrated Characterisation of Energy, Clouds, Atmospheric state, and Precipitation at Summit - Aerosol Cloud Experiment (ICECAPS-ACE) project. These data were continued through the 3 year extension to the ICECAPS-ACE project called ICECAPS-MELT.

The Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) was a joint-mission between NASA and the French space agency Centre National d'Etudes Spatiales. The main objectives of the mission was to supply unique data set of vertical cloud and aerosol profiles. This dataset contains cloud and aerosol lidar level 2 5km cloud layer version 3-02 data derived from Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) Level 1B product at 5 km horizontal resolution, with full complement of diagnostic and quality assurance parameters. The data provide a range of parameters including vertical profile of cloud layers and optical depth. Version 3-30 was released in April, 2013. This version incorporates two ancillary input files updated from those used in versions 3-01 and 3-02: GEOS-5 processing system version 5.9.1 from version 5.2; and the enhanced Air Force Weather Authority (AFWA) Snow and Ice Datasets. The resulting changes are relatively small.

This dataset contains concentrations of condensation nuclei (> 5 nm diameter) measured at the surface at the Summit Station Greenland using a GRIMM 5.4 Condensation Particle Counter (CPC). Data are 1 minute averages concatenated into monthly files. These data were collected as part of the joint Natural Environmental Research Council (NERC) and US National Science Foundation (NSF) -funded Integrated Characterisation of Energy, Clouds, Atmospheric state, and Precipitation at Summit - Aerosol Cloud Experiment (ICECAPS-ACE) project.

This dataset contains the near-surface temperature profile from four temperature/ humidity sensors distributed on the 15 m tower at Summit Station, Greenland, detected by four Vaisala HMP155 Temperature/Relative Humidity sensors with a heated probe. Data are 1 minute averages concatenated into monthly files. These data were collected as part of the joint Natural Environmental Research Council (NERC) and US National Science Foundation (NSF) -funded Integrated Characterisation of Energy, Clouds, Atmospheric state, and Precipitation at Summit - Aerosol Cloud Experiment (ICECAPS-ACE) project. These data were continued through the 3 year extension to the ICECAPS-ACE project called ICECAPS-MELT.

The Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) was a joint-mission between NASA and the French space agency Centre National d'Etudes Spatiales. The main objectives of the mission was to supply unique data set of vertical cloud and aerosol profiles. This dataset contains cloud and aerosol lidar level 1B version 3-01 data product, which contains processed Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) Level 0 Data and post processed ephemeris data, celestial data and converted payload status data. In version 3-01, L1B product uses enhanced daytime calibration, updated laser energy calculation algorithm, corrections to the CALIPSO orbit tracks and updated parameters.

The Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) was a joint-mission between NASA and the French space agency Centre National d'Etudes Spatiales. The main objectives of the mission was to supply unique data set of vertical cloud and aerosol profiles. This dataset contains cloud and aerosol lidar level 2 vertical feature mask version 3-01 Data Product, which describes the horizontal and vertical distribution of the cloud and the aerosol layers observed by the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP). In Version 3-01, the L2 products use an enhanced daytime calibration, improved cloud-aerosol discrimination algorithm with removal of a bug in the cloud clearing code, and the newly introduced cloud thermodynamic phase assessment algorithm.