The need to characterize the increase and distribution of greenhouse gases is a first order scientific goal of the atmospheric composition and climate communities. The HIAPER Pole-to-Pole Observations (HIPPO) program will provide global, meridional coverage, via vertical profiles throughout the depth of the troposphere enabling closure and inversion of global budgets of critical greenhouse gases (e.g. carbon dioxide, CO2; carbon monoxide, CO; and methane, CH4), and related long-lived tracers and ratios (e.g. the oxygen/nitrogen ratio, O2/N2). This suite of chemical measurements, made from 80 N to 70 S, and repeated over approximately six monthly intervals, will provide a unique and definitive data set, to be used in inversion and other global modeling analyses of carbon cycle gases.
Observed gradients in the hemispheric concentrations of greenhouse gases are critical to our ability to predict the fate of anthropogenic emissions of carbon gases. Previous chemical transport modeling studies used to infer CO2 surface fluxes, sources and sinks have been generally constrained to using boundary layer CO2 concentrations. The field experiments will thus take advantage of transformative capabilities newly available to the atmospheric science community provided by the use of the HIAPER G-V aircraft platform.
This work is supported under the NSF Carbon and Water in the Earth System solicitation, an interdisciplinary funding opportunity from the Directorate of Geosciences.
The HIAPERS Pole to Pole (HIPPO) project made truly ground breaking contributions to atmospheric and climate science by completing the first broad survey of the chemical composition of the atmosphere from nearly pole to pole and throughout the year. No comparable atmospheric survey with such broad spatial and temporal coverage had previously been attempted. HIPPO was inspired by the classic GEOSECS program, which mapped the distribution of long-lived tracers in the ocean, and revolutionized the field of chemical oceanography. The vast data sets collected and now publicly available from HIPPO may have a similarly broad legacy. The Scripps Institution of Oceanography contributed to HIPPO by providing support for the collection and analysis of whole air samples and for in-flight observations. The Scripps program included making measurements of CO2 and O2 concentrations and measurements of the isotopic composition of CO2 from the whole air samples. The data provide comprehensive insights into seasonal exchanges of CO2 and O2 with land and oceans and into vertical mixing rates within the atmosphere. The data will assist in helping to determine the sources and sinks of CO2 and O2 with the ocean, and provide benchmarks for comparing with future changes. The Scripps program also conducted measurements of the Ar/N2 ratio of the air samples which can help to quantify changes in ocean heat storage with season and rates of mixing in the lower stratosphere. Scripps has also led a study using HIPPO data to assess how the patterns of variations in atmospheric CO2 have changed over the last 50 years, taking advantage of the previous major atmospheric survey that was conducted in the Northern Hemisphere from 1958 to 1961 as part of the so-called International Geophysical Year (IGY).
