From the earliest observations of ozone in the lower atmosphere in the 19th century, both measurement methods and the portion of the globe observed have evolved and changed. These methods have different uncertainties and biases, and the data records differ with respect to coverage (space and time), information content, and representativeness. In this study, various ozone measurement methods and ozone datasets are reviewed and selected for inclusion in the historical record of background ozone levels, based on relationship of the measurement technique to the modern UV absorption standard, absence of interfering pollutants, representativeness of the well-mixed boundary layer and expert judgement of their credibility. There are significant uncertainties with the 19th and early 20th-century measurements related to interference of other gases. Spectroscopic methods applied before 1960 have likely underestimated ozone by as much as 11% at the surface and by about 24% in the free troposphere, due to the use of differing ozone absorption coefficients.
There is no unambiguous evidence in the measurement record back to 1896 that typical mid-latitude background surface ozone values were below about 20 nmol mol–1, but there is robust evidence for increases in the temperate and polar regions of the northern hemisphere of 30–70%, with large uncertainty, between the period of historic observations, 1896–1975, and the modern period (1990–2014). Independent historical observations from balloons and aircraft indicate similar changes in the free troposphere. Changes in the southern hemisphere are much less. Regional representativeness of the available observations remains a potential source of large errors, which are difficult to quantify.
The great majority of validation and intercomparison studies of free tropospheric ozone measurement methods use ECC ozonesondes as reference. Compared to UV-absorption measurements they show a modest (~1–5% ±5%) high bias in the troposphere, but no evidence of a change with time. Umkehr, lidar, and FTIR methods all show modest low biases relative to ECCs, and so, using ECC sondes as a transfer standard, all appear to agree to within one standard deviation with the modern UV-absorption standard. Other sonde types show an increase of 5–20% in sensitivity to tropospheric ozone from 1970–1995.
Biases and standard deviations of satellite retrieval comparisons are often 2–3 times larger than those of other free tropospheric measurements. The lack of information on temporal changes of bias for satellite measurements of tropospheric ozone is an area of concern for long-term trend studies.
Thompson, Elizabeth J.; Moum, James N.; Fairall, Christopher W.; Rutledge, Steven A.;
Published Date:
2019
Source:
Journal of Geophysical Research: Oceans,;
124, 897–924;
Description:
Stratification of the upper few meters of the ocean limits the penetration depth of wind mixing and the vertical distribution of atmospheric fluxes. Significant density stratification at depths ≤ 5 m was observed in 38% of a 2‐month data set from...
We used data from 333 continuous Global Positioning System stations, including 26 stations installed in 2006–2007 as part of a collaborative EarthScope experiment, to investigate how deformation is distributed near the Rio Grande Rift. Our previous...
Observations of shallow fault creep reveal increasingly complex time‐dependent slip histories that include quasi‐steady creep and triggered as well as spontaneous accelerated slip events. Here we report a recent slow slip event on the southern Sa...
Ryu, Y. H.; Hodzic, A.; Descombes, G.; Hu, M.; Barre, J.;
Published Date:
2019
Source:
Journal of Geophysical Research: Atmospheres, 124, 13576-13592
Description:
Accuracy of cloud predictions in numerical weather models can considerably impact ozone (O-3) forecast skill. This study assesses the benefits in surface O-3 predictions of using the Rapid Refresh (RAP) forecasting system that assimilates clouds as w...
Thompson, Anne M.; Smit, Herman G. J.; Witte, Jacquelyn C.; Stauffer, Ryan M.; Johnson, Bryan J.; Morris, Gary; von der Gathen, Peter; Van Malderen, Roeland; Davies, Jonathan; Allaart, Ankie Piters Marc; Posny, Françoise; Kivi, Rigel; Cullis, Patrick; Nguyen, Thi Hoang Anh; Corrales, Ernesto; Machinini, Tshidi; da Silva, Francisco R.; Paiman, George; Thiong’o, Kennedy; Zainal, Zamuna; Brothers, George B.; Wolff, Katherine R.; Nakano, Tatsumi; Stübi, Rene; Romanens, Gonzague; Coetzee, Gert J. R.; Diaz, Jorge A.; Mitro, Sukarni; Mohamad, Maznorizan; Ogino, Shin-Ya;
Published Date:
2019
Source:
Bull. Amer. Meteor. Soc. (2019) 100 (1): 155–171.
Description:
The ozonesonde is a small balloon-borne instrument that is attached to a standard radiosonde to measure profiles of ozone from the surface to 35 km with ∼100-m vertical resolution. Ozonesonde data constitute a mainstay of satellite calibration and ...
White, Allen B.; Moore, Benjamin J.; Gottas, Daniel J.; Neiman, Paul J.;
Published Date:
2019
Source:
Bull. Amer. Meteor. Soc. (2019) 100 (1): 55–70.
Description:
During winter 2016/17, California experienced numerous heavy precipitation events linked to land-falling atmospheric rivers (ARs) that filled reservoirs and ended a severe, multiyear drought. These events also caused floods, mudslides, and debris flo...
Yu, P. F.; Froyd, K. D.; Portmann, R. W.; Toon, O. B.; Freitas, S. R.; Bardeen, C. G.; Brock, C.; Fan, T. Y.; Gao, R. S.; Katich, J. M.; Kupc, A.; Liu, S.; Maloney, C.; Murphy, D. M.; Rosenlof, K. H.; Schill, G.; Schwarz, J. P.; Williamson, C.;
Published Date:
2019
Source:
Geophysical Research Letters, 46, 1061-1069.
Description:
Convective systems dominate the vertical transport of aerosols and trace gases. The most recent in situ aerosol measurements presented here show that the concentrations of primary aerosols including sea salt and black carbon drop by factors of 10 to ...
An intensive coordinated airborne and ground-based measurement study was conducted in the Fayetteville Shale in northwestern Arkansas during September and October 2015 to compare and explain potential discrepancies between top-down and bottom-up esti...
Yang, H.; Waugh, D. W.; Orbe, C.; Patra, P. K.; Jockel, P.; Lamarque, J. F.; Tilmes, S.; Kinnison, D.; Elkins, J. W.; Dlugokencky, E. J.;
Published Date:
2019
Source:
Geophysical Research Letters, 46, 1113-1120.
Description:
Two recent studies using sulfur hexafluoride (SF6) observations to evaluate interhemispheric transport in two different ensembles of atmospheric chemistry models reached different conclusions on model performance. We show here that the different conc...
Reitman, Nadine G.; Mueller, Karl J.; Tucker, Gregory E.; Gold, Ryan D.; Briggs, Richard W.; Barnhart, Katherine R.;
Published Date:
2019
Source:
JGR Solid Earth (2019). 124(12): 13427-13451
Description:
Slip distribution, slip rate, and slip per event for strike‐slip faults are commonly determined by correlating offset stream channels—under the assumption that they record seismic slip—but offset channels are formed by the interplay of tectonic...
Stillwell, Robert A.; Neely III, Ryan R.; Thayer, Jeffrey P.; Walden, Von P.; Shupe, Matthew D.; Miller, Nathaniel B.;
Published Date:
2019
Source:
Journal of Geophysical Research: Atmospheres, 124, 12141-12156
Description:
Ice crystals commonly adopt a horizontal orientation under certain aerodynamic and electrodynamic conditions that occur in the atmosphere. While the radiative impact of horizontally oriented ice crystals (HOIC) has been theoretically studied with res...
The yields of the six declared underground nuclear tests at the North Korean test site are estimated using high‐frequency teleseismic P wave amplitude modeling and waveform equalization of short‐period teleseismic P waves and regional Pn signals....
The cryosphere, which comprises a large portion of Earth’s surface, is rapidly changing as a consequence of global climate change. Ice, snow, and frozen ground in the polar and alpine regions of the planet are known to directly impact atmospheric c...
Mazzotti, Giulia; Currier, William Ryan; Deems, Jeffrey S.; Pflug, Justin M.; Lundquist, Jessica D.; Jonas, Tobias;
Published Date:
2019
Source:
Water Resources Research, 55(7): 6198–6216
Description:
The retrieval of detailed, co‐located snow depth and canopy cover information from airborne lidar has advanced our understanding of links between forest snow distribution and canopy structure. In this study, we present two recent high‐resolution ...
Serreze, Mark C.; Barrett, Andrew P.; Crawford, Alex D.; Woodgate, Rebecca A.;
Published Date:
2019
Source:
Journal of Geophysical Research: Oceans, 124, 9317–9337
Description:
The Bering Strait oceanic heat transport influences seasonal sea ice retreat and advance in the Chukchi Sea. Monitored since 1990, it depends on water temperature and factors controlling the volume transport, assumed to be local winds in the strait a...
The Eastern Cordillera of Colombia, in the northern Andes, is an example of an orogen in which Mesozoic basins were compressed during the Cenozoic, forming a ~2,500‐m‐high plateau in its northern portion. Significant shortening and crustal thicke...
Yarce, J.; Sheehan, A. F.; Nakai, J. S.; Schwartz, S. Y.; Mochizuki, K.; Savage, M. K.; Wallace, L. M.; Henrys, S. A.; Webb, S. C.; Ito, Y.; Abercrombie, R. E.; Fry, B.; Shaddox, H.; Todd, E. K.;
Published Date:
2019
Source:
JGR Solid Earth (2019). 124(5): 4751-5766
Description:
In 2014–2015, the Hikurangi Ocean Bottom Investigation of Tremor and Slow Slip experiment deployed seafloor absolute pressure gauges and ocean bottom seismometers directly above a large slow slip event, allowing examination of the relationship betw...
We propose a time series modeling approach based on nonlinear dynamical systems to recover the underlying dynamics and predictability of streamflow and to produce projections with identifiable skill. First, a wavelet spectral analysis is performed on...
Morrison, A. L.; Kay, J. E.; Frey, W. R.; Chepfer, H.; Guzman, R.;
Published Date:
2019
Source:
Journal of Geophysical Research: Atmospheres, 124, 1003-1020
Description:
Over the next century, the Arctic is projected to become seasonally sea ice‐free. Assessing feedback between clouds and sea ice as the Arctic loses sea ice cover is important because of clouds' radiative impacts on the Arctic surface. Here we inves...
Takahashi, H.; Lebsock, M. D.; Richardson, M.; Marchand, R.; Kay, J. E.;
Published Date:
2019
Source:
Journal of Geophysical Research: Atmospheres, 124, 7270-7285
Description:
Cloud feedbacks remain the largest source of uncertainty in future climate predictions. Simulations robustly project an increase in cloud height, which is supported by some observational evidence. However, how much of this increasing trend is due to ...
Oltmans, S. J.; Cheadle, L. C.; Johnson, B. J.; Schnell, R. C.; Helmig, D.; Thompson, A. M.; Cullis, P.; Hall, E.; Jordan, A.; Sterling, C.; McClure-Begley, A.; Sullivan, J.; McGee, T. J.; Wolfe, D.;
Published Date:
2019
Source:
Elem Sci Anth, 7(1), p.6.
Description:
Data from ground-based ozone (O3) vertical profiling platforms operated during the FRAPPE/DISCOVER-AQ campaigns in summer 2014 were used to characterize key processes responsible for establishing O3 profile development in the boundary layer in the No...