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K. W. Bowman

Publications and source records attributed to K. W. Bowman.

2 recordsLinked to original sources

A U.S. scientific community vision for sustained earth observations of greenhouse gases to support local to global action

Managing carbon stocks in the land, ocean, and atmosphere under changing climate requires a globally-integrated view of carbon cycle processes at local and regional scales. The growing Earth Observation (EO) record is the backbone of this multi-scale system, providing local information with discrete coverage from surface measurements and regional information at global scale from satellites. Carbon flux information, anchored by inverse estimates from spaceborne Greenhouse Gas (GHG) concentrations, provides an important top-down view of carbon emissions and sinks, but currently lacks global continuity at assessment and management scales (< 100 km). Partial-column data can help separate signals in the boundary layer from the overlying atmosphere, providing an opportunity to enhance surface sensitivity and bring flux resolution down from that of column-integrated data (100–500 km). Based on a workshop held in September 2024, the carbon cycle community envisions a carbon observation system leveraging GHG partial columns in the lower and upper troposphere to weave together information across scales from surface and satellite EO data, and integration of top- down/bottom-up analyses to link process understanding to global assessment.

AGU Advances

Evidence for two surface ruptures in the past 500 years on the San Andreas fault at Frazier Mountain, California

We conducted paleoseismic studies in a closed depression along the San Andreas fault on the north flank of Frazier Mountain near Frazier Park, California. We recognized two earthquake ruptures in our trench exposure and interpreted the most recent rupture, event 1, to represent the historical 1857 earthquake. We also exposed evidence of an earlier surface rupture, event 2, along an older group of faults that did not rerupture during event 1. Radiocarbon dating of the stratigraphy above and below the earlier event constrains its probable age to between A.D. 1460 and 1600. Because we documented continuous, unfaulted stratigraphy between the earlier event horizon and the youngest event horizon in the portion of the fault zone exposed, we infer event 2 to be the penultimate event. We observed no direct evidence of an 1812 earthquake in our exposures. However, we cannot preclude the presence of this event at our site due to limited age control in the upper part of the section and the possibility of other fault strands beyond the limits of our exposures. Based on overlapping age ranges, event 2 at Frazier Mountain may correlate with event B at the Bidart fan site in the Carrizo Plain to the northwest and events V and W4 at Pallett Creek and Wrightwood, respectively, to the southeast. If the events recognized at these multiple sites resulted from the same surface rupture, then it appears that the San Andreas fault has repeatedly failed in large ruptures similar in extent to 1857.

California