HIAPER Pole-to-Pole Observations

HIAPER Pole-to-Pole Observations. The HIAPER Pole-to-Pole Observations (HIPPO) was a landmark global atmospheric research program conducted between 2009 and 2011. It utilized the advanced HIAPER aircraft to measure greenhouse gases and related tracers across the full vertical extent of the atmosphere, from the Arctic to the Antarctic. The campaign provided an unprecedented three-dimensional snapshot of the global atmosphere, revolutionizing understanding of carbon cycles and climate forcing.

Overview and Objectives

The primary objective of HIPPO was to create the first comprehensive, global-scale mapping of over 80 atmospheric gases and particles from the Earth's surface to the stratosphere. Scientists from the National Center for Atmospheric Research (NCAR) and partner institutions, including Harvard University and NOAA, designed the mission to address critical unknowns in the global carbon cycle. A key goal was to quantify the geographic distribution of sources and sinks for major greenhouse gases like carbon dioxide and methane. The program aimed to validate and improve the performance of global climate models, such as those used by the Intergovernmental Panel on Climate Change (IPCC), by providing critical in-situ data often missing from satellite observations.

Aircraft and Instrumentation

The campaign's central platform was the HIAPER (High-performance Instrumented Airborne Platform for Environmental Research), a highly modified Gulfstream V business jet operated by NCAR. This aircraft could cruise at altitudes up to 51,000 feet and had a range exceeding 7,000 miles, enabling long-duration, high-altitude missions over remote oceans. The cabin was outfitted with a sophisticated payload of over 20 instruments developed by leading U.S. laboratories. This suite included advanced spectrometers from Harvard University, high-precision gas analyzers from Scripps Institution of Oceanography, and aerosol samplers from the University of Hawaii. The integration of these instruments allowed for simultaneous, calibrated measurements of trace gases, aerosols, and meteorological parameters throughout each flight.

Flight Tracks and Campaigns

HIPPO consisted of five intensive measurement campaigns conducted between January 2009 and September 2011. Each campaign involved a series of transects from Colorado to the Arctic and then south over the Pacific Ocean to the Southern Ocean near Antarctica. Flights originated from bases like Boulder, Colorado and Anchorage, Alaska, with refueling stops in locations such as American Samoa and Christchurch, New Zealand. The flight tracks were carefully planned to sample all seasons and major atmospheric regimes, including the deep convection regions of the tropics and the pristine air over the Southern Ocean. This systematic, repeated sampling strategy was unique and provided a time-evolving picture of atmospheric composition.

Key Scientific Findings

Data from HIPPO led to several transformative discoveries about the global atmosphere. It provided direct evidence of a much larger than expected Northern Hemisphere reservoir of black carbon and other pollutants, which was being transported into the Arctic. The missions precisely quantified the strong seasonal "breathing" of the carbon dioxide cycle, particularly from Northern Hemisphere forests. Over the remote Southern Ocean, HIPPO measurements revealed it as a more significant sink for atmospheric carbon than previous models had estimated. The campaign also documented the global distribution and transport of potent greenhouse gases like methane and nitrous oxide, identifying previously underestimated oceanic sources. These findings have been published in high-impact journals like Science and Nature.

Data Access and Legacy

All data from HIPPO are publicly archived and accessible through the Earth Observing Laboratory data repository at NCAR. This extensive dataset continues to be a vital resource for the international research community, used for model evaluation and studies in atmospheric chemistry, climate science, and carbon cycle research. The program's legacy includes training a generation of early-career scientists in advanced airborne measurement techniques. The success of HIPPO directly influenced the design of subsequent major field campaigns, such as ATom (Atmospheric Tomography Mission) by NASA, and continues to inform assessments by the Intergovernmental Panel on Climate Change regarding global carbon budgets and climate projections.

Category:Atmospheric research Category:Climate change assessment and attribution Category:Scientific projects