20th Century Atmospheric River Archive for Western North America and Europe

General Description

This datasets provides 6-hourly instantaneous atmospheric river absence-presence time series for 13 sub-regions along the coastlines of Western North America and Europe, as well the corresponding Integrated Water Vapor (IVT) values and exceeded climatological quantiles. These data were retrieved from 3 distinct reanalyses:

1. ERA-20C, 1900-2010, 1.125 degrees resolution, here termed "era20c"

2. NOAA-CIRES 20th Century Reanalysis version 2, 1900-2012, 2 degrees resolution, here termed "c20", ARs were retrieved from instantaneous ensemble-mean data.

3. ECMWF ERA-Interim, 1979-2014, 0.75 degrees resolution, here termed "interim"

The file structure is as in this example:

ar_Brands_v0_interim_scalifornia_JFMAOND_1979_2014.nc

translates to:

ar_<algorithm name>_<version>_<underlying dataset>_<target region as illustrated in fig_studyregions.pdf>_<considered months>_<start year>_<end_year>.nc

The 13 study regions are indicated in <fig_studyregions.pdf> attached below and described in Brands et al. (2017). The lat-lon coordinates of each region are provided in the netCDF files.

For western North America and Europe the October-through-April and October-through-March season is covered, respectively. The compressed netCDF4 files offered here come with detailed metadata information. For generating the present dataset, the initial version of the AR detection and tracking algorithm developed in my PhD thesis was used (here referred to as version 0, see Brands et al. 2017 for a full description). Although newer algorithm versions have become available in the framework of the Atmospheric River Method Intercomparison Project (ARTMIP, see Rutz et al. 2019), the initial version 0 was specifically developed for detecting landfalling ARs along the coastlines of Western North America and Europe. The correct functioning was supervised by eye for hundreds, if not thousands of cases.

The 9 distinct AR detection and tracking methods contained in each netCDF file (coined "method 0,1...8" in there) use distinct climatological percentile thresholds to 1) detect ARs along the coastline (the detection percentile, termed "prct_detect") and then "crawl" upwards the flow guided by the strongest IVT above the tracking percentile ("prct_track") and by the respective U and V components until a minimum length of 2000 km is reached. The results obtained from the 9 methods thus differ in AR intensity.

The netCDF files of the present dataset have been recompiled from the non-standard .mat files generated in my PhD thesis during the years 2013-2017. For the target regions in Europe, the content of the present dataset partly overlaps with the non-standard dataset previously published at http://dx.doi.org/10.13140/RG.2.2.14711.32160. The target regions in western North America have been newly included and are only available from the present dataset.

Contact: Swen Brands, brandssf@ifca.unican.es

References

Brands, S., Gutiérrez, J.M. & San-Martín, D. (2017). Twentieth-century atmospheric river activity along the west coasts of Europe and North America: algorithm formulation, reanalysis uncertainty and links to atmospheric circulation patterns. Climate Dynamics 48, 2771–2795. https://doi.org/10.1007/s00382-016-3095-6

Compo, G.P., Whitaker, J.S., Sardeshmukh, P.D., Matsui, N., Allan, R.J., Yin, X., Gleason, B.E., Vose, R.S., Rutledge, G., Bessemoulin, P., Brönnimann, S., Brunet, M., Crouthamel, R.I., Grant, A.N., Groisman, P.Y., Jones, P.D., Kruk, M.C., Kruger, A.C., Marshall, G.J., Maugeri, M., Mok, H.Y., Nordli, Ø., Ross, T.F., Trigo, R.M., Wang, X.L., Woodruff, S.D. and Worley, S.J. (2011), The Twentieth Century Reanalysis Project. Q.J.R. Meteorol. Soc., 137: 1-28, https://doi.org/10.1002/qj.776

Dee, D.P., Uppala, S.M., Simmons, A.J., Berrisford, P., Poli, P., Kobayashi, S., Andrae, U., Balmaseda, M.A., Balsamo, G., Bauer, P., Bechtold, P., Beljaars, A.C.M., van de Berg, L., Bidlot, J., Bormann, N., Delsol, C., Dragani, R., Fuentes, M., Geer, A.J., Haimberger, L., Healy, S.B., Hersbach, H., Hólm, E.V., Isaksen, L., Kållberg, P., Köhler, M., Matricardi, M., McNally, A.P., Monge-Sanz, B.M., Morcrette, J.-.-J., Park, B.-.-K., Peubey, C., de Rosnay, P., Tavolato, C., Thépaut, J.-.-N. and Vitart, F. (2011), The ERA-Interim reanalysis: configuration and performance of the data assimilation system. Q.J.R. Meteorol. Soc., 137: 553-597, https://doi.org/10.1002/qj.828

Poli, P., and Coauthors, 2016: ERA-20C: An Atmospheric Reanalysis of the Twentieth Century. J. Climate, 29, 4083–4097, https://doi.org/10.1175/JCLI-D-15-0556.1

Rutz, J. J., Shields, C. A., Lora, J. M., Payne, A. E., Guan, B., Ullrich, P., et al. (2019). The Atmospheric River Tracking Method Intercomparison Project (ARTMIP): Quantifying uncertainties in atmospheric river climatology. Journal of Geophysical Research: Atmospheres, 2019; 124: 13777– 13802. https://doi.org/10.1029/2019JD030936