Journal of Geophysical Research - Atmospheres

Supporting Information for

Evidence for added value of convection-permitting models for studying changes in extreme precipitation

E. P. Meredith1, D. Maraun1,2, V. A. Semenov1,3,4,5, W. Park1

1GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany

2Wegener Center for Climate and Global Change, University of Graz, Graz, Austria

3A.M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences, ,

4P.P. Shirshov Institute of Oceonology, Russian Academy of Sciences, Moscow, Russia

5Institute of Geography, Russian Academy of Sciences, Moscow, Russia

Contents of this file

Text S1 (with accompanying figures S1-3) Figures S4 to S6

Introduction

This supporting information document provides Text S1 and Figures S4 to S6, as referred to in the main document.

1 Text S1 – Synoptic Discussion of the Precipitation Extreme

A slow moving cyclone was centered over the north-eastern on July 6 th 2012, advecting warm and moist air towards the Krymsk region (Figure S1). The atmospheric profile early on the 6th, from the down coast station of (44.10N/39.07E), shows the lower atmosphere to be saturated at most levels below 500 hPa and primarily conditionally unstable below 750 hPa (Figure S2). Analysis of the lower troposphere reveals the development of a south-westerly low- level jet to the south and east of Krymsk. Maximum wind speeds of over 13 m/s at the 925 hPa level (Figure S3) provided a rich source of shoreward moisture advection, giving rise to the first wave of convection.

Later that night, convective cells formed at the head of an equivalent potential temperature (theta- e) ridge before merging into a larger organized mesoscale convective system (MCS). A steady infusion of warm and moist air was fed along the theta-e ridge axis towards the developing MCS, where its high energy content fueled vigorous convection and the subsequent second wave of heavy rain.

During the event, the Krymsk station recorded 156 mm of precipitation on the night from July 6th- 7th (171 mm in 24 hours). The nearby station at recorded almost twice as much precipitation in the same period [Kotlyakov et al., 2013].

2 Figure S1. Column integrated precipitable water (colors, kg m-2) and sea level pressure (hPa, contours) on the 6th of July, 2012, at 18Z. Based on NCEP Final Analyses. Krymsk is marked with an 'x'. Adapted from Meredith et al., 2015.

3 Figure S2. Skew-T log-P diagram based on radiosonde data from Tuapse (44.10N/39.07E) on July 6th 2012 at 00Z.

4 Figure S3. Wind direction (vectors) and strength (shading or vectors) at 925 hPa on July 6th 2012 at 06Z. Based on NCEP Final Analyses.

5 Supporting Information – Figures S4-S6

Figure S4. Impact and cause of increased precipitation intensity. As in Figure 4 of the main text, except for the first wave of precipitation.

6 Figure S5. Impact of increased precipitation intensity. As in Figure 5 of the main text, except for the first wave of precipitation.

7 Figure S6. Extreme precipitation response to enhanced SST forcing with different convective parametrization schemes. As in Figure 8 of the main text, except for the first wave of convection. Note that the response of the Tiedtke scheme (cyan) has not been scaled in this plot, unlike in the equivalent plot in the main text.

8 References

Kotlyakov, V. M. et al. (2013), Flooding of July 6–7, 2012, in the town of Krymsk, Regional Research of Russia 3.1: 32-39.

Meredith et al. (2015), Crucial role of Black Sea warming in amplifying the 2012 Krymsk precipitation extreme, Nature Geosci., 8, 615-619.

National Centers for Environmental Prediction/National Weather Service/NOAA/U.S. Department of Commerce. 2000, updated daily. NCEP FNL Operational Model Global Tropospheric Analyses, continuing from July 1999. Research Data Archive at the National Center for Atmospheric Research, Computational and Information Systems Laboratory. http://dx.doi.org/10.5065/D6M043C6. Accessed 20 Nov 2013.

Tuapse radiosonde data - http://weather.uwyo.edu/upperair/sounding.html

9