Performance of RegCM4 convective permitting version in precipitation - - PowerPoint PPT Presentation

Performance of RegCM4 convective permitting version in precipitation extremes over southeastern South America: preliminary results

Rosmeri P. da Rocha*, M. Llopart, M. L. Bertolli, Fernandez J., Chou S., Coppola E., Doyle M., Feijoo M., Gutierrez J.M., Lavin-Gullon A., Solman S.

*Universidade de São Paulo

CORDEX-FLAGSHIP PILOT STUDY IN SOUTHEASTERN SOUTH AMERICA (SESA)

The CORDEX Flagship Pilot Studies (FPS) are targeted experimental setups to better addressing key scientific topics MOTIVATIONS

• Extreme precipitation events over SESA are

becoming more frequent and more intense. These events have large socio-economic and hydrologic impacts.

• There is a need for better understanding and

modeling these precipitation extremes.

• There are limited ESD studies in the region.
• There is a need for developing RCM and ESD

coordinated actions. Courtesy of M. L. Bertolli

CORDEX-FLAGSHIP PILOT STUDY IN SOUTHEASTERN SOUTH AMERICA (SESA)

MAIN OBJECTIVES:

• to study multi-scale processes and interactions

(convection, local, regional and remote processes, including the co-behaviour of processes) that result in these extreme precipitation events;

• and to develop actionable climate information

from multiple sources (statistical and dynamical downscaling products) based on co-production with the impact and user community. Courtesy of M. L. Bertolli

CORDEX-FLAGSHIP PILOT STUDY IN SOUTHEASTERN SOUTH AMERICA (SESA)

ARGENTINA Department of Atmospheric and Ocean Sciences – University of Buenos Aires ARGENTINA CIMA-National Council of National Council

• f Scientific and Technical Research

(CONICET) ARGENTINA Argentine Association of Regional Consortia for Agricultural Experimentation (AACREA) BRAZIL University of São Paulo (USP) BRAZIL São Paulo State University (UNESP) BRAZIL Center for Weather Forecasting and Climate Studies (CPTEC) BRAZIL National Institute for Space Research BRAZIL Brazilian Agricultural Research Corporation (EMBRAPA) CZECH REPUBLIC Charles University in Prague SPAIN CSIC / University of Cantabria ITALY Abdus Salam International Centre for Theoretical Physics (ICTP) URUGUAY Department of Atmospheric Sciences, University of the Republic

Partners Courtesy of M. L. Bertolli WRF ETA RegCM4 WRF Models

As part of CORDEX-FPS the aims of this study is to understand the ability of RegCM4 convective permitting version to simulate precipitation extremes over SESA; Strategy: three case studies within one of the warm seasons with higher number of extreme events: from November 2009 to March 2010;

Objective and strategy

(a) Figura 13: N´ umero total de raios (flashes) observados pelo LIS em cada regi˜ ao de 0,25¶ × 0,25¶ de latitude e longitude entre 1998–2011, ilustrando a matriz FLlis.

Total number of lightnings from 1998-2011 observed by LIS. ( Anselmo, 2015) SESA

Test Protocols:

• 1. Three extreme events:

Case1: 18-02-2010 00:00 UTC - event peaks 20/21-02-2010 stations max: 127 mm/day Case2: 17-01-2010 00:00 UTC - event peaks 19-01-2010 station max: 152 mm/day Case3: 20-11-2009 00:00 UTC - event peaks 22-11-2009 station max: 115 mm/day

• 2. Two simulation types

Weather mode (WM) – simulation starts ~12 hours before initial phase of each one of three extreme events; Climate mode (CM) – continuos simulation (seasonal) starting at 01-10-2009 ending at 31-03-2010.

Test Protocols:

• 3. Two domains: ~ 24 (CSAM-20i) and 4 (SESA-4i) km of grid spacing;
• 4. Initial and boundary conditions:

CSAM-20i experiments are nested in ERA-Interim reanalysis; SESA-4i experiments are nested in CSAMi-20i;

• 5. Models: RegCM4, WRF and ETA.
• 6. RegCM4 non-hydrostatic core

RegCM4 physic options: CSAM-20i: uses Tiedke and Kain-Fritsch convective schemes, respectively, over the land and ocean; SUBEX for large-scale precipitation SESA-4i: WSM5 microphysics scheme (convective permitting) CLM4.5: to solve surface processes in both simulations

SESA-4i

CSAM-20i

Climate mode (CM) simulations (CSAM-20i x SESA-4i) : Climatology for Nov/2009-March/2010

TRMM CPC Simulations capture the

• bserved maximum of

rainfall in southeast SA; More intense precipitation is simulated by CSAM-20i Impact of convective permitting simulation: Decreases in the intensitity

• f the seasonal rainfall à

values closer to the

• bservation.

SESA-4i CSAM-20i

Climate mode climatology: November/2009-March/2010 CSAM-20i x SESA-4i - zoom

TRMM CPC CSAM-20i SESA-4i

Month-to-month variability is similar in both simulations; Higher agreement with

• bservations in convective

permitting simulation: spatial pattern and intensity;

Monthly mean precipitation CSAM-20i SESA-4i

2 4 6 8 10 12 14 16 18 3 6 9 12 15 18 21

mm/day Time (UTC)

Long Simulations - Diurnal Cycle

Stations CSAM-20i SESA-4i TRMM

Location of the stations from INMet/Brazil

CM simulations of the precipitation diurnal cycle (mm/day)

Climatology for Nov/2009 to March/2010

Stations: precipition peaks at 12 and 15 UTC (9 and 12 LT) à it is correctely reproduced by both simulations; Simulations overestimate the intensity of rainfall during the day; During the nigth (21, 0, 3 UTC) à intensity biases are small Most of the times SESA-4i (convection permiting) is closer of local observations than CSAM-20i;

Cases study: Climate mode x weather mode Parametrization (CSAM-20i) x coventive permitting (SESA-4i) simulations

Case1: evolution of observed daily precipitation from 19 to 21 February

CMORPH CPC 19 20 21 February Very intense pcp (above 120 mm/day) between 19-20 February

stations max: 127 mm/day

Pcp continues intense in CMORPH from 20 to 21

Precipitation initiates from 18 to 19 February

CMORPH hourly rainfall

Case1: simulations x observation

CSAM-20i SESA-4i CM WM CMORPH February 20 Simulations are able to reproduce the general aspects (location and intensity)

• f the extreme event

CM: location and area of the more intense rainfall are better reproduced by convective permintting (SESA-4i) simulation; WM: more intense rainfall is slightly southwestward shifted compared to CMORPH in CSAM-20i; SESA-4i simulates better the location, but underestimates the area with intense rainfall.

21 22 November

Case3: evolution of observed daily precipitation from 21 to 22 November

CMORPH CPC Precipiation intensifies on November 22 CPC: Between 100-120 mm/day CMORPH: above 120 mm/day

Case3: simulations x observation

Precipitation above 120 mm/day is simulated by both CSAM-20i and SESA-4i CM: location of more intense precipiation is closer to the CMORPH in convective permiting (SESA-4i) simulation; WM: simulations displace northward the maximum rainfall compared to CMORPH CSAM-20i SESA-4i

Case3: precipitation diurnal cycle

10 20 30 40 50 60 70 80 3 6 9 12 15 18 21

mm/day Time (UTC)

Diurnal Cycle_Case3

Stations CSAM-20i SESA-4i

WM (Weather Mode simulations) Simulated and observed precipiation peaks at 15 UTC (12 LT); Simulations overestimate the intensity during most of the times; During the day (9-18 UTC) à overestimation is greater in convective permitting (SESA-4i) than in CSAM-20i.

Preliminary conclusions and next

For one of warm seasons with higher number of extreme events (Nov/2009- March/2010): the two simulations captured the general aspects of the seasonal precipitation; Convective permitting simulation presents greater agreement with

• bservations than parameterized one, including the diurnal cycle of

precipitation in (CM). Initial results with convective permitting RegCM4 version are encouraging to study extreme events over Southeast South America. Next:

• to quantify the improvement of the simulations using the convective

permitting version (statistical index, PDFs, diurnal cycle, etc.);

• to compare RegCM4 simulations with other participant models (WRF and

ETA);

• to understand the environment conditions favoring these extreme events.

Thanks! Obrigada!