Report on WGNE* activities

Report on WGNE* activities Keith Williams and Ayrton Zadra (WGNE co-chairs) * WGNE = Working Group on Numerical Experimentation 9th Scientific Steering Committee of the World Weather Research Programme 24-27 October 2016 Geneva, Switzerland

WGNE s mission http://www.wmo.int/pages/about/sec/rescrosscut/resdept_wgne.html Jointly established by the WCRP-JSC and the WMO-CAS. Responsibility of fostering the development of models for use in weather prediction and climate studies on all time scales and diagnosing and resolving shortcomings. aka building better physical models! We do this through Identification of systematic errors common to many models. Sharing diagnostic tools and techniques to get to the root of the error. Sharing knowledge around sensitivity of errors to model formulation (parametrizations, dynamical core, etc.). Work with other groups (e.g. GASS & GLASS) to develop solutions. Page 2 25/10/2016

Selection of current WGNE activities Drag project comparison on momentum budgets MJO-Task Force Seamless working (AMIP & Transpose-AMIP methodologies) Establishing importance of aerosols level of complexity required across different timescales Cloudy-radiance comparing methods used in data assimilation Grey-zone joint project with GASS Evaluation and verification NWP performance (more variables - TC s, precipitation) Polar verification Climate metrics Issues with verification Page against 3 25/10/2016 own analysis

Motivation for WGNE Drag Project: importance/impact of parametrization of orographic processes Example: Impact of orographic blocking in the Canadian global NWP model implementation of blocking (Lott & Miller): RMSE reduction of ~ 7m enhancement/adjustment of blocking and PBL: RMSE reduction of ~ 3m Page 4 25/10/2016

WGNE Drag Project design Field to compare: surface stress* i.e. the force parallel to the surface, per unit area, as applied by the wind on the earth's surface (land or water). Phase 1 of Drag Project: Compare the parametrized components of this surface stress In a typical forecast model, it s partly resolved & partly parametrized: Basic output requested: x- and y-components of the parametrized stress averaged over the 1st day (24h) of a month of forecasts proposed months: Jan and Jul 2012. Page 5 25/10/2016

WGNE Drag Project Phase 1 ICON 13km DWD pbl, sgo, res Page 6 25/10/2016

Comparison of averaged surface torque components Jan 2012 Page 7 25/10/2016

WGNE DRAG-project: inter-comparison of stress fields u-component of stress Jan 2012 18-24h average IFS (ECMWF) UM (UKMetO) PBL SGO Page 8 25/10/2016 N/m2

WGNE DRAG-project: recent developments Latest developments, ongoing and planned activities Website and 1 st report available (http://collaboration.cmc.ec.gc.ca/science/rpn/drag_project/) Results presented at 21 st Symposium on Boundary Layer and Turbulence (Jun 2014, Leeds, UK) World Weather Open Science Conference (Aug 2014, Montreal, Canada) Workshop on Angular Momentum Budget (April 2015 at Univ. Reading, organized by Dr. T. Shepherd) 2016 SPARC Gravity Wave Symposium (May 2016, State College, PA, USA) ECWMF/WCRP/WWRP workshop on Drag processes and their links to large-scale circulation, in Sep 2016 recommendations that followed: better theoretical understanding of drag better understanding of inter-model differences using high resolution simulations, and observations, as well as new techniques to understand model errors and improve/constrain the representation of orographic drag in models. Page 9 25/10/2016 (http://www.ecmwf.int/en/learning/workshops-and-seminars/drag-processes-and-their-linkslarge-scale-circulation)

WGNE MJO Task Force (Steve Woolnough and Daehyun Kim) Overall Goal: Facilitate improvements in the representation of the MJO in weather and climate models to increase the predictive skill of the MJO and related weather and climate phenomena. Organized into 5 Subprojects: Process-oriented diagnostics/metrics for MJO simulation (leads: D. Kim, P. Xavier, E. Maloney, T. Miyakawa, C. Risi, R. Neale) Evaluation of real time forecasts of tropical intraseasonal variability (leads: J.-Y. Lee, M. Wheeler, J. Gottschalck) Assessment of CMIP5 model capability to simulate realistic intraseasonal variability (leads: K. Sperber, D. Kim, M.-S. Ahn) MJO TF + GASS Multi-Model Diabatic Processes Experiment (leads: D. Waliser, X. Jiang, J. Petch, P. Xavier, S. Woolnough, N. Klingaman) 10 Develop, coordinate, and promote analyses of MJO air-sea interaction (leads: C. DeMott, N. Klingaman, S. Woolnough)

MJO simulation capability - CMIP5 models CLIVAR MJO simulation diagnostics (CLIVAR MJO WG 2009) applied to CMIP5 models by Min-Seop Ahn (Seoul National University) Results posted online (http://climate.snu.ac.kr/mjo_diagnostics/index.htm) 11 Lag-correlation diagram (eastward propagation) Diagnostics that have applied include EOF Lag-correlation (left) Space-time power spectrum Wheeler-Kiladis diagram CEOF analysis Mean state Relationship with process-oriented diag. Research paper based on the analysis in preparation

Realtime MJO Index dynamical model forecast activity Yellow Lines: 20 Individual Members, Green Line: Ensemble Mean RMM1 and RMM2 values for the most recent 40 days and forecasts for the next 30 days Light gray shading: 90% of forecasts, dark gray shading: 50% of forecasts MJO Task Force U.S. CLIVAR MJO Working Group and MJO Task Force adopted this metric as a uniform diagnostic for MJO identification, skill evaluation and display of MJO forecasts Realtime data contributions to CPC from operational international centers further supported by WGNE http://www.cpc.ncep.noaa.gov/products/precip/cwlink/mjo/clivar/clivar_wh.shtml 12

Assessment of Forecast Skill Bivariate correlation for several models and benchmarks Boreal winter forecast skill is better Forecast skill linked to initial amplitude ECMWF, UK Metoffice performed the best Forecast skill as a function of MJO initial phase Varying structure as a function of forecast model 13

MJO TF/GASS Multi-Model Diabatic Processes Experiment Goal: Develop, coordinate, and promote analyses of the multi scale interactions and processes that are a critical component of the MJO, both in observations and by exploiting recent advances in high resolution modeling frameworks, with particular emphasis on vertical structure and diabatic processes. Key Outcomes: Generation of extensive model data archive of climate experiments and 2- and 20-day MJO hindcasts available on the Earth System Grid at https://earthsystemcog.org/projects/gass-yotc-mip/ Detailed description and diagnostic analysis of these simulations in four manuscripts (Xiang et al. 2015; Xavier et al. 2015; Klingaman et al. 2015a,b) Key results: MJO fidelity is related to realism of rainfall-moistening profile relationship MJO fidelity is related to realism of rainfall- lower to middle tropopsheric RH relationship (consistent with the process-oriented diagnostic above) Lack of importance of diabatic heating structure to MJO fidelity 14 Little relationship between success of MJO hindcasts and MJO fidelity in long climate simulations

New MJOTF-S2S Joint Effort on the Maritime Continent (MC) 15 Goal: To improve understanding of MJO propagation through the Maritime Continent region, where prediction skill is limited by model deficiencies and the complexity of interactions among the atmosphere, ocean, and land-surface. Motivation: The MJO represents one of the high priority subprojects of the WMO Subseasonal-to-Seasonal (S2S) prediction program. S2S and the MJO Task Force deemed the interaction of the MC with the MJO as a high priority research question that has significant bearing on shortcomings/improving operational MJO predictions Motivating Principles: To better understand processes and improve prediction Practicalities and Opportunities (i.e. why now?) Significant interest across S2S, MJOTF, and AAMP Existing modeling resources (S2S, MJOTF-GASS, and ISVHE databases) Impending Years of the Maritime Continent project. Opportunity to help define objectives of campaign and make scientific progress Tieh-Yong Koh and Adrian Matthews have joined TF to assist this effort 2016 boreal spring MJOTF-S2S-YMC Singapore workshop being developed on issues related to subseasonal variability, simulation and prediction in the MC region

Selection of recommendations/actions from WGNE-31 For new WCRP strategy: closer working with the weather side with specific suggestion that WMAC be extended to cover WWRP modelling groups - e.g. DAOS, PDEF, S2S. note the cross-timescale work of GEWEX Ensemble prediction: Junichi Ishida and Caroline Reynolds to provide a summary of centre views on ensemble size, resolution and complexity and available computational power to optimize benefits in order to address the WWRP request related the development of the new WWRP Implementation Plan. PPP/YOPP: Michael Ek and Francois Engelbrecht to engage with Thomas Jung as liaison to PPP and YOPP. WGNE members make their centres aware of YOPP and contact PPP through Michael Ek and Francois Engelbrecht in instances where there is a commitment to contribute. Michael Ek and Francois Engelbrecht Page 16 25/10/2016 to discuss with YOPP possible projects on drag and momentum processes.

Selection of recommendations/actions from WGNE-31 S2S: The co-chairs of the MJO Task Force should come to an agreement regarding on responsibilities between MJO Task Force and S2S on the assessment of MJO index forecast and other related matters and then to inform WGNE and WWRP accordingly. Suggest to S2S to take forward what has been done so far on by WGNE on aerosols to seasonal timescales. DAOS: WGNE members to consider possible suggestions for new DAOS members to cover the areas as highlighted in Tom Hamill s WGNE-31 presentation. The GAW SSC Chair to be invited as an ex-officio member of WGNE. That the TC verification information compiled by WGNE be brought to the attention of the WWRP Working Group on Tropical Meteorological Research and CBS. Page 17 25/10/2016

Selection of recommendations/actions from WGNE-31 GEWEX: Michael EK to provide feedback to GEWEX on the gap related to atmosphere ocean sea ice exchanges. WGNE co-chair to communicate the WGNE concern about the lack of GASS co-chairs to GEWEX WGNE co-chair to request GEWEX to prepare a paragraph which can be sent to WGNE members on how young scientist can get involved in GEWEX activities (participation, leading projects, chair etc.). WGNE co-chair to inform GEWEX on the key systematic errors not currently covered by projects: a. convective rain over orography, b. light rain (convective, drizzle problems), c. boundary layer cloud, fog, Stratocumulus over land, d. 2-4 km resolution models which have too intense rainfall rates, and e. aerosols Page 18 25/10/2016

5th WGNE workshop on systematic errors in weather and climate models 19-23 June 2017, Montreal, Quebec, Canada http://collaboration.cmc.ec.gc.ca/science/rpn/wgne_wse/en/ hosted by Environment and Climate Change Canada (ECCC) goal is to increase understanding of the nature and cause of errors in models used for weather and climate prediction important dates: - submission of abstracts: opening on 15 Dec 2016; ending on 28 Jan 2017 - registration for accepted abstracts: opening on 06 Feb 2017; ending on 28 Feb 2017 (note: registration fee will be Can$ 150.) please help publicize Page 19 25/10/2016

Next WGNE annual meeting (WGNE-32) October 2017 at the UK Met Office, joint with the other WCRP modelling groups (WGCM, WGSIP, WGOMD) May wish to consider a meeting with the WWRP modelling groups (e.g. S2S, PDEF, DAOS) Page 20 25/10/2016 in the future?...

Montreal Thank you and I hope to see you in Montreal in June 2017 Page 21 25/10/2016