CPEXCV-Dropsondes_1 is the dropsonde data files collected during the Convective Processes Experiment - Cabo Verde (CPEX-CV). Data collection for this product is complete.Seeking to better understand atmospheric processes in regions with little data, the Convective Processes Experiment – Cabo Verde (CPEX-CV) campaign conducted by NASA is a continuation of the CPEX – Aerosols & Winds (CPEX-AW) campaign that took place between August to September 2021. The campaign will take place between 1-30 September 2022 and will operate out of Sal Island, Cabo Verde with the primary goal of investigating atmospheric dynamics, marine boundary layer properties, convection, the dust-laden Saharan Air Layer, and their interactions across various spatial scales to improve understanding and predictability of process-level lifecycles in the data-sparse tropical East Atlantic region.CPEX-CV will work towards its goal by addressing four main science objectives. The first goal is to improve understanding of the interaction between large-scale environmental forcings such as the Intertropical Convergence Zone (ITCZ), Saharan Air Layer, African easterly waves, and mid-level African easterly jet, and the lifecycle and properties of convective cloud systems, including tropical cyclone precursors, in the tropical East Atlantic region. Next, observations will be made about how local kinematic and thermodynamic conditions, including the vertical structure and variability of the marine boundary layer, relate to the initiation and lifecycle of convective cloud systems and their processes. Third, CPEX-CV will investigate how dynamical and convective processes affect size dependent Saharan dust vertical structure, long-range Saharan dust transport, and boundary layer exchange pathways. The last objective will be to assess the impact of CPEX-CV observations of atmospheric winds, thermodynamics, clouds, and aerosols on the prediction of tropical Atlantic weather systems and validate and interpret spaceborne remote sensors that provide similar measurements.To achieve these objectives, the NASA DC-8 aircraft will be deployed with remote sensing instruments and dropsondes that will allow for the measurement of tropospheric aerosols, winds, temperature, water vapor, and precipitation. Instruments onboard the aircraft include the Airborne Third Generation Precipitation Radar (APR-3), lidars such as the Doppler Aerosol WiNd Lidar (DAWN), High Altitude Lidar Observatory (HALO), High Altitude Monolithic Microwave Integrated Circuit (MMIC) Sounding Radiometer (HAMSR), Advanced Vertical Atmospheric Profiling System (AVAPS) dropsonde system, Cloud Aerosol and Precipitation Spectrometer (CAPS), and the Airborne In-situ and Radio Occultation (AIRO) instrument. Measurements taken by CPEX-CV will assist in moving science forward from previous CPEX and CPEX-AW missions, the calibration and validation of satellite measurements, and the development of airborne sensors, especially those with potential for satellite deployment.

PEM-West-B_Merge_Data is the merge data collected onboard the DC-8 aircraft during the Pacific Exploratory Mission (PEM) West B suborbital campaign. Data collection for this product is complete.During 1983-2001, NASA conducted a collection of field campaigns as a part of the Global Tropospheric Experiment (GTE) for developing advanced instrumentation to quantify atmospheric trace gases’ sources, sinks, and distribution. Among those was PEM, which intended to improve the scientific understanding of human influence on tropospheric chemistry. Part of the PEM field campaigns (PEM-West) were conducted over the northwestern Pacific region, considered the only major region in the northern hemisphere that is “relatively” free from direct anthropogenic influences. PEM-West was a part of the East Asian/North Pacific Regional Study (APARE). The overarching objectives of PEM-West were 1) to investigate the atmospheric chemistry of ozone (O3) and its precursors over the northwestern Pacific, including the examination of their natural budgets as well as the impact of anthropogenic sources; and 2) to investigate the atmospheric sulfur cycle over the region with emphasis on the relative importance and influence of continental vs marine sulfur sources. The two phases of PEM-West were conducted during differing seasons due to contrasting tropospheric outflow from Asia. The first phase, PEM-West A, was conducted over the western Pacific region off the eastern coast of Asia from September-October 1991, a season characterized by the predominance of flow from mid-Pacific regions. The second phase, PEM-West B, was conducted from February-March 1994, a period characterized by maximum air mass outflow. To accomplish its objectives, the PEM-West campaign deployed the NASA DC-8 aircraft across the northwestern Pacific to gather latitudinal, longitudinal, and vertical profile sampling, as well as extensive sampling in both the marine boundary layer and free troposphere. The aircraft was equipped with a comprehensive suite of in-situ instrument packages for characterization of photochemical precursors, intermediate products, and airmass tracers, including O3, nitric oxide (NO), peroxyacetyl nitrate (PAN), nitrogen oxides (NOy), nonmethane hydrocarbons (NMHCs), hydrogen peroxide (H2O2), acetic acid (CH3OOH), carbon monoxide (CO), and formaldehyde (CH2O). Collectively, these measurements enabled the analyses of the photochemical production/destruction of O3 and the distribution of precursor species. In addition, the DC-8 was equipped with instruments for collecting sulfur measurements, including dimethyl sulfide (DMS), carbonyl sulfide (COS), sulfur dioxide (SO2), and carbon disulfide (CS2). Instruments that collected aerosol composition and microphysical properties were also aboard the DC-8. Both missions deployed a Differential Absorption Lidar (DIAL) system for measurements of O3 vertical profiles above and below the aircraft. One highlight of the project was that flight nine of PEM-West A flew over Typhoon Mireille while it made landfall on the coast of Japan. This allowed for a flight by the DC-8 to study the role of typhoons in the transport of trace gases. Detailed descriptions related to the motivation, implementation, and instrument payloads are available in the PEM-West A overview paper and the PEM-West B overview paper. A collection of the publications based on PEM-West A and B observation are available in the Journal of Geophysical Research special issues: Pacific Exploratory Mission-West Phase A and Pacific Exploratory Mission-West, Phase B (PEM-West B).

CPEXAW-Dropsondes_1 is the dropsonde data files collected during the Convective Processes Experiment - Aerosols & Winds (CPEX-AW). Data collection for this product is complete.The Convective Processes Experiment – Aerosols & Winds (CPEX-AW) campaign was a joint effort between the US National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA) with the primary goal of conducting a post-launch calibration and validation activities of the Atmospheric Dynamics Mission-Aeolus (ADM-AEOLUS) Earth observation wind Lidar satellite in St. Croix. CPEX-AW is a follow-on to the Convective Processes Experiment (CPEX) field campaign which took place in the summer of 2017. In addition to joint calibration/validation of ADM-AEOLUS, CPEX-AW studied the dynamics related to the Saharan Air Layer, African Easterly Waves and Jets, Tropical Easterly Jet, and deep convection in the InterTropical Convergence Zone (ITCZ). CPEX-AW science goals include:• Better understanding interactions of convective cloud systems and tropospheric winds as part of the joint NASA-ESA Aeolus Cal/Val effort over the tropical Atlantic;• Observing the vertical structure and variability of the marine boundary layer in relation to initiation and lifecycle of the convective cloud systems, convective processes (e.g., cold pools), and environmental conditions within and across the ITCZ;• Investigating how the African easterly waves and dry air and dust associated with Sahara Air Layer control the convectively suppressed and active periods of the ITCZ;• Investigating interactions of wind, aerosol, clouds, and precipitation and effects on long range dust transport and air quality over the western Atlantic.In order to successfully achieve the objectives of the campaign, NASA deployed its DC-8 aircraft equipped with an Airborne Third Generation Precipitation Radar (APR-3), Doppler Aerosol WiNd Lidar (DAWN), High Altitude Lidar Observatory (HALO), High Altitude Monolithic Microwave Integrated Circuit (MMIC) Sounding Radiometer (HAMSR), and dropsondes. This campaign aims to provide useful material to atmospheric scientists, meteorologists, lidar experts, air quality experts, professors, and students. The Atmospheric Science Data Center (ASDC) archives the dropsonde, HALO, and DAWN data products for CPEX-AW. For additional datasets please visit the Global Hydrometeorology Resource Center (GHRC).

The AAMH CPEX dataset contains products obtained from the MetOp-A, MetOp-B, NOAA-18, and NOAA-19 satellites. These data were collected in support of the NASA Convective Processes Experiment (CPEX) field campaign. The CPEX field campaign took place in the North Atlantic-Gulf of America-Caribbean Sea region from 25 May to 25 June 2017. CPEX conducted a total of sixteen DC-8 missions from 27 May to 24 June. The CPEX campaign collected data to help explain convective storm initiation, organization, growth, and dissipation in the North Atlantic-Gulf of America-Caribbean Oceanic region during the early summer of 2017. These data are available from May 26, 2017, through July 15, 2017, and are available in netCDF-4 format.

PEM-West-A_Merge_Data is the merge data collected onboard the DC-8 aircraft during the Pacific Exploratory Mission (PEM) West A suborbital campaign. Data from the Differential Absorption of CO, CH4, N2O Measurements (DACOM) instrument, laser induced fluorescence, grab samples, chemiluminescence, and gas chromatography are featured in this collection. Data collection for this product is complete.During 1983-2001, NASA conducted a collection of field campaigns as a part of the Global Tropospheric Experiment (GTE) for developing advanced instrumentation to quantify atmospheric trace gases’ sources, sinks, and distribution. Among those was PEM, which intended to improve the scientific understanding of human influence on tropospheric chemistry. Part of the PEM field campaigns (PEM-West) were conducted over the northwestern Pacific region, considered the only major region in the northern hemisphere that is “relatively” free from direct anthropogenic influences. PEM-West was a part of the East Asian/North Pacific Regional Study (APARE). The overarching objectives of PEM-West were 1) to investigate the atmospheric chemistry of ozone (O3) and its precursors over the northwestern Pacific, including the examination of their natural budgets as well as the impact of anthropogenic sources; and 2) to investigate the atmospheric sulfur cycle over the region with emphasis on the relative importance and influence of continental vs marine sulfur sources. The two phases of PEM-West were conducted during differing seasons due to contrasting tropospheric outflow from Asia. The first phase, PEM-West A, was conducted over the western Pacific region off the eastern coast of Asia from September-October 1991, a season characterized by the predominance of flow from mid-Pacific regions. The second phase, PEM-West B, was conducted from February-March 1994, a period characterized by maximum air mass outflow. To accomplish its objectives, the PEM-West campaign deployed the NASA DC-8 aircraft across the northwestern Pacific to gather latitudinal, longitudinal, and vertical profile sampling, as well as extensive sampling in both the marine boundary layer and free troposphere. The aircraft was equipped with a comprehensive suite of in-situ instrument packages for characterization of photochemical precursors, intermediate products, and airmass tracers, including O3, nitric oxide (NO), peroxyacetyl nitrate (PAN), nitrogen oxides (NOy), nonmethane hydrocarbons (NMHCs), hydrogen peroxide (H2O2), acetic acid (CH3OOH), carbon monoxide (CO), and formaldehyde (CH2O). Collectively, these measurements enabled the analyses of the photochemical production/destruction of O3 and the distribution of precursor species. In addition, the DC-8 was equipped with instruments for collecting sulfur measurements, including dimethyl sulfide (DMS), carbonyl sulfide (COS), sulfur dioxide (SO2), and carbon disulfide (CS2). Instruments that collected aerosol composition and microphysical properties were also aboard the DC-8. Both missions deployed a Differential Absorption Lidar (DIAL) system for measurements of O3 vertical profiles above and below the aircraft. One highlight of the project was that flight nine of PEM-West A flew over Typhoon Mireille while it made landfall on the coast of Japan. This allowed for a flight by the DC-8 to study the role of typhoons in the transport of trace gases. Detailed descriptions related to the motivation, implementation, and instrument payloads are available in the PEM-West A overview paper and the PEM-West B overview paper. A collection of the publications based on PEM-West A and B observation are available in the Journal of Geophysical Research special issues: Pacific Exploratory Mission-West Phase A and Pacific Exploratory Mission-West, Phase B (PEM-West B).

PEM-Tropics-B_Merge_Data is the merge data collected onboard during the Pacific Exploratory Mission (PEM) Tropics B suborbital campaign. Data collection for this product is complete.From 1983-2001, NASA conducted a collection of field campaigns as part of the Global Tropospheric Experiment (GTE). Among those was PEM, which intended to improve the scientific understanding of human influence on tropospheric chemistry. Part of the PEM field campaigns were focused on the tropical Pacific region (PEM-Tropics) which was recognized as a “very large chemical vessel.” The overarching science objective was to assess the anthropogenic impact on tropospheric oxidizing power. A secondary objective was to investigate the impact of atmospheric sulfur chemistry, including oxidation of marine biogenic emission of dimethyl sulfide (DMS) on aerosol loading and radiative effect, which is of critical importance in the assessment of global climate change. The PEM-Tropics mission was conducted in two phases to contrast the influence of biomass burning in the dry season and the “relatively clean” wet season. The first, PEM-Tropics A, was carried out during the end of the dry season (August-September 1996), and the second, PEM-Topics B, was conducted during the wet season (March-April 1999). To accomplish its objectives, PEM-Tropics enlisted the NASA DC-8 and P-3B aircrafts to carry out longitudinal and latitudinal surveys at various altitudes as well as vertical profile sampling across the Pacific basin. Both aircrafts were equipped with in-situ instruments measuring hydroperoxyl radicals (HOx), ozone (O3), photochemical precursors (including, reactive nitrogen species and non-methane hydrocarbon species), and intermediate products (e.g., hydrogen peroxide (H2O2), formaldehyde (CH2O), and acetic acid (CH3OOH). The P3-B in-situ instrument payload also included a direct measurement of hydroxyl (OH) for both missions, while the OH and hydroperoxyl radical (HO2) measurements were added to DC-8 aircraft for PEM-Tropics B. Taking advantage of its excellent low altitude capability, the P-3B was instrumented with a comprehensive sulfur measurement package and conducted pseudo-Lagragian sampling for evaluating DMS oxidation chemistry, including measurements of DMS, sulfur dioxide (SO2), sulfuric acid (H2SO4), and methylsulfonic acid (MSA) as well as the first airborne measurement of dimethyl sulfoxide (DMSO) during PEM-Tropics B. More importantly, it was the first time that DMS (the source), OH and O3 (primary oxidants), and products (DMSO, MSA, H2SO4, SO2) were measured simultaneously aboard an aircraft in the tropical pacific. These observations, specifically DMSO, presented a substantial challenge to the DMS oxidation kinetics to this day. The DC-8 aircraft was equipped with the Differential Absoprtion Lidar (DIAL) during PEM-Tropics A, and the differential absorption lidars DIAL and LASE during PEM-Tropics B. These lidars provided real-time information for fine tuning the flight tracks to capture sampling opportunities. The lidar data products themselves provide valuable information of vertical profiles of ozone as well as aerosol and water vapor in tropical Pacific Furthermore, both aircrafts were fitted with instruments for aerosol composition and microphysical property measurements. Detailed description related to the motivation, implementation, and instrument payloads are available in the PEM-Tropics A overview paper and the PEM-Tropics B overview paper. Most of the publications based on PEM-Tropics A and B observations are available in the Journal of Geophysical Research special issues: Pacific Exploratory Mission-Tropics A and NASA Global Tropospheric Experiment Pacific Exploratory Mission in the Tropics Phase B: Measurement and Analyses (PEM-Tropics B), while other publications such as Nowak et al. (2001) were published prior to the special issues.