Nonlinear Processes in Geosciences

NPG Paper of the Month: “Beyond univariate calibration: verifying spatial structure in ensembles of forecast fields”

Tommaso Alberti October 2, 2020

Example binary exceedance verification field and a subset of ensemble fields with representative FTE histogram for threshold τ=0 found using 5000 samples. Dark blue regions indicate threshold exceedance. All verification fields have correlation length a0=2 and ensemble fields have correlation length aM=1,2,3 in rows A, B, and C, respectively. FTE histograms are density histograms with dotted line y=1 and corresponding β-score (left) and β-bias (right) annotated. License: https://doi.org/10.5194/npg-27-411-2020.

The August 2020 NPG Paper of the Month award goes to Josh Jacobson and colleagues for their paper “Beyond univariate calibration: verifying spatial structure in ensembles of forecast fields” (https://doi.org/10.5194/npg-27-411-2020). The ability to know the future has long been sought after and coveted. Yet, in contrast to prophecies and crystal balls, modern methods of prediction are ...[Read More]

NPG Paper of the Month: “Simulation-based comparison of multivariate ensemble post-processing methods”

Tommaso Alberti September 29, 2020

Exemplary results for three variants of one of the simulation settings. Boxplots show comparisons to the standard ECC approach, with positive values indicating improvements in performance, measured in terms of two multivariate evaluation functions. The horizontal gray stripe indicates a region where differences in performance are not statistically significant with respect to the Diebold-Mariano (DM) test. License: https://doi.org/10.5194/npg-27-349-2020.

The June 2020 NPG Paper of the Month award goes to Sebastian Lerch and colleagues for their paper “Simulation-based comparison of multivariate ensemble post-processing methods” (https://doi.org/10.5194/npg-27-349-2020). Sebastian Lerch is a researcher at the Faculty of Mathematics of the Karlsruhe Institute Technology (KIT). He has a background in mathematics and statistics, his resear ...[Read More]

NPG Paper of the Month “Anthropocene climate bifurcation”

Tommaso Alberti September 24, 2020

Arctic surface temperature change projected to year 2300 (relative to year 2000 mean temperature of -28.90 °C), with linearly increasing ocean heat transport F_O . (a) With constant F_A = 104 W/m2, there is a jump in temperature for RCP 8.5 but not for the other choices of RCP. (b) The same as (a) except that in addition to increasing F_O , the atmosphere heat transport F_A also increases linearly from 104 to 129 W/m2 . Now upward transitions occur on both RCP 8.5 and 6.0, as indicated by the arrows. License: https://doi.org/10.5194/npg-27-391-2020.

The July 2020 NPG Paper of the Month award goes to Kolja Kypke, William Langford and Allan Willms, for their paper “Anthropocene climate bifurcation” (https://doi.org/10.5194/npg-27-391-2020). All three authors work at the University of Guelph, in Guelph, Ontario, Canada. William Langford did his PhD at the California Institute of Technology in 1971 under the supervision of Herbert Kel ...[Read More]

Is climate change making the weather more extreme?

Davide Faranda September 11, 2020

NOAA PSL weather forecasts of temperature anomaly at 850hPa (~1500m.a.s.l.) shows a deep negative anomaly on Central US, leading to snowfalls. Credits: NOAA.

Denver, Sept. 06: it is midday and Jonathan and Maria are sunbathing at City Park. They feel uncomfortable as the temperature has already reached 36°C. While they decide to go back home, their favoured weather app displays an unbelievable snowstorm watch for Tuesday Sept. 08. The forecast turns out to be rather accurate as all Colorado experiences one of the earliest snowstorms on record in Septem ...[Read More]