.. _recipes_wenzel16jclim: Multiple ensemble diagnostic regression (MDER) for constraining future austral jet position =========================================================================================== Overview -------- `Wenzel et al. (2016)`_ use multiple ensemble diagnostic regression (MDER) to constrain the CMIP5 future projection of the summer austral jet position with several historical process-oriented diagnostics and respective observations. The following plots are reproduced: * Absolute correlation between the target variable and the diagnostics. * Scatterplot between the target variable and the MDER-calculated linear combination of diagnostics. * Boxplot of RMSE for the unweighted multi-model mean and the (MDER) weighted multi-model mean of the target variable in a pseudo-reality setup. * Time series of the target variable for all models, observations and MDER predictions. * Errorbar plots for all diagnostics. * Scatterplots between the target variable and all diagnostics. .. _`Wenzel et al. (2016)`: https://journals.ametsoc.org/doi/full/10.1175/JCLI-D-15-0412.1 Available recipes and diagnostics --------------------------------- Recipes are stored in recipes/ * recipe_wenzel16jclim.yml Diagnostics are stored in diag_scripts/ * austral_jet/asr.ncl * austral_jet/main.ncl * mder/absolute_correlation.ncl * mder/regression_stepwise.ncl * mder/select_for_mder.ncl User settings in recipe ----------------------- #. Preprocessor * ``extract_region``: Region extraction. * ``extract_levels``: Pressure level extraction. * ``area_statistics``: Spatial average calculations. #. Script austral_jet/asr.ncl * ``season``, *str*: Season. * ``average_ens``, *bool*, optional (default: ``False``): Average over all given ensemble members of a climate model. * ``wdiag``, *array of str*, optional: Names of the diagnostic for MDER output. Necessary when MDER output is desired. * ``wdiag_title``, *array of str*, optional: Names of the diagnostic in plots. #. Script austral_jet/main.ncl * ``styleset``, *str*: Style set used for plotting the multi-model plots. * ``season``, *str*: Season. * ``average_ens``, *bool*, optional (default: ``False``): Average over all given ensemble members of a climate model. * ``rsondes``, *array of str*, optional: Additional observations used in the plot but not for MDER output. * ``rsondes_file``, *array of str*, optional: Paths to the additional observations Necessary when ``rsondes`` is given. * ``rsondes_yr_min``, *int*, optional: Minimum year for additional observations. Necessary when ``rsondes`` is given. * ``rsondes_yr_max``, *int*, optional: Maximum year for additional observations. Necessary when ``rsondes`` is given. * ``wdiag``, *array of str*, optional: Names of the diagnostic for MDER output. Necessary when MDER output is desired. * ``wdiag_title``, *array of str*, optional: Names of the diagnostic in plots. * ``derive_var``, *str*, optional: Derive variables using NCL functions. Must be one of ``"tpp"``, ``"mmstf"``. * ``derive_latrange``, *array of float*, optional: Latitude range for variable derivation. Necessary if ``derive_var`` is given. * ``derive_lev``, *float*, optional: Pressure level (given in *Pa*) for variable derivation. Necessary if ``derive_var`` is given. #. Script mder/absolute_correlation.ncl * ``p_time``, *array of int*: Start years for future projections. * ``p_step``, *int*: Time range for future projections (in years). * ``scal_time``, *array of int*: Time range for base period (in years) for anomaly calculations used when ``calc_type = "trend"``. * ``time_oper``, *str*: Operation used in NCL ``time_operation`` function. * ``time_opt``, *str*: Option used in NCL ``time_operation`` function. * ``calc_type``, *str*: Calculation type for the target variable. Must be one of ``"trend"``, ``"pos"``, ``"int"``. * ``domain``, *str*: Domain tag for provenance tracking. * ``average_ens``, *bool*, optional (default: ``False``): Average over all given ensemble members of a climate model. * ``region``, *str*, optional: Region used for area aggregation. Necessary if input of target variable is multidimensional. * ``area_oper``, *str*, optional: Operation used in NCL ``area_operation`` function. Necessary if multidimensional is given. * ``plot_units``, *str*, optional (attribute for ``variable_info``): Units for the target variable used in the plots. #. Script mder/regression_stepwise.ncl * ``p_time``, *array of int*: Start years for future projections. * ``p_step``, *int*: Time range for future projections (in years). * ``scal_time``, *array of int*: Time range for base period (in years) for anomaly calculations used when ``calc_type = "trend"``. * ``time_oper``, *str*: Operation used in NCL ``time_operation`` function. * ``time_opt``, *str*: Option used in NCL ``time_operation`` function. * ``calc_type``, *str*: Calculation type for the target variable. Must be one of ``"trend"``, ``"pos"``, ``"int"``. * ``domain``, *str*: Domain tag for provenance tracking. * ``average_ens``, *bool*, optional (default: ``False``): Average over all given ensemble members of a climate model. * ``smooth``, *bool*, optional (default: ``False``): Smooth time period with 1-2-1 filter. * ``iter``, *int*, optional: Number of iterations for smoothing. Necessary when ``smooth`` is given. * ``cross_validation_mode``, *bool*, optional (default: ``False``): Perform cross-validation. * ``region``, *str*, optional: Region used for area aggregation. Necessary if input of target variable is multidimensional. * ``area_oper``, *str*, optional: Operation used in NCL ``area_operation`` function. Necessary if multidimensional is given. * ``plot_units``, *str*, optional (attribute for ``variable_info``): Units for the target variable used in the plots. #. Script mder/select_for_mder.ncl * ``wdiag``, *array of str*: Names of the diagnostic for MDER output. Necessary when MDER output is desired. * ``domain``, *str*: Domain tag for provenance tracking. * ``ref_dataset``, *str*: Style set used for plotting the multi-model plots. * ``average_ens``, *bool*, optional (default: ``False``): Average over all given ensemble members of a climate model. * ``derive_var``, *str*, optional: Derive variables using NCL functions. Must be one of ``"tpp"``, ``"mmstf"``. Variables --------- * *ta* (atmos, monthly, longitude, latitude, pressure level, time) * *uajet* (atmos, monthly, time) * *va* (atmos, monthly, longitude, latitude, pressure level, time) * *ps* (atmos, monthly, longitude, latitude, time) * *asr* (atmos, monthly, longitude, latitude, time) Observations and reformat scripts --------------------------------- * ERA-Intermin (*ta*, *uajet*, *va*, *ps*) * CERES-EBAF (*asr*) References ---------- * Wenzel, S., V. Eyring, E.P. Gerber, and A.Y. Karpechko: Constraining Future Summer Austral Jet Stream Positions in the CMIP5 Ensemble by Process-Oriented Multiple Diagnostic Regression. J. Climate, 29, 673–687, doi:10.1175/JCLI-D-15-0412.1, 2016. Example plots ------------- .. _fig_wenzel16jclim_1: .. figure:: /recipes/figures/wenzel16jclim/CMPI5_uajet-pos_rcp45_20ystep_FIG1.png :align: center :width: 80% Time series of the the target variable (future austral jet position in the RCP 4.5 scenario) for the CMIP5 ensemble, observations, unweighted multi-model mean projections and (MDER) weighted multi-model mean projections. .. _fig_wenzel16jclim_2: .. figure:: /recipes/figures/wenzel16jclim/CMPI5_uajet-pos_rcp45_20ystep_FIG2b.png :align: center :width: 80% Scatterplot of the target variable (future austral jet position in the RCP 4.5 scenario) vs. the MDER-determined linear combination of diagnostics for the CMIP5 ensemble. .. _fig_wenzel16jclim_3: .. figure:: /recipes/figures/wenzel16jclim/CMPI5_uajet-pos_rcp45_20ystep_FIG3.png :align: center :width: 80% Boxplot for the RMSE of the target variable for the unweighted and (MDER) weighted multi-model mean projections in a pseudo-reality setup. .. _fig_wenzel16jclim_4: .. figure:: /recipes/figures/wenzel16jclim/ta_trop250_ta_DJF_trend.png :align: center :width: 80% Trends in tropical DJF temperature at 250hPa for different CMIP5 models and observations. .. _fig_wenzel16jclim_5: .. figure:: /recipes/figures/wenzel16jclim/uajet_H-SH_c.png :align: center :width: 80% Scatterplot of the target variable (future austral jet position in the RCP 4.5 scenario) vs. a single diagnostic, the historical location of the Southern hemisphere Hadley cell boundary for the CMIP5 ensemble.