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26 Mar
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MJO and Teleconnections 26 Mar, 00:03
25 Mar
26 Feb
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Dear Colleagues,
We are resuming the monthly series of webinars hosted by the WWRP/WCRP/S2S/MJO-Teleconnections sub-project. Please join us for the January webinar.
Title: Intrinsic Uncertainty in the Euro-Atlantic Response to the MJO heating in boreal winter: Ongoing Results from ECMWF Re-Forecasts
Speaker: David Straus, George Mason UniversityDate: Thursday, January 28, 2021
Time: 10:30am EST | 3:30pm UTCAbstract
While the Euro-Atlantic response to the MJO has been well studied in reanalysis and a hierarchy of models, a factor that is often overlooked is the uncertainty in the response due to the intrinsic variability in the full diabatic heating during even a single phase of the MJO.
We examine the heating variability within large (51-member) ensembles of boreal winter reforecasts from the ECMWF model, focusing on forecasts initialized in phases 2 and 3 of the MJO (with heating anomalies located over the Indian Ocean). Results will be shown from new experimental reforecasts in which all the ensemble members utilize identical initial conditions, with the only difference between ensemble members arising from the application of stochastic physics in the target Indian Ocean region. (The stochastic physics is turned off outside the target region.)
The resulting uncertainty (ensemble spread) in the Euro-Atlantic response during the first few weeks of the forecasts is also examined, as well as some discussion of ongoing work to link the response uncertainties to those in the heating. The Euro-Atlantic response is seen to be similar to the traditional MJO response early in the forecast (MJO phases 2/3 leading to the NAO+ regime). However, later on in the forecast variability in the heating over the Pacific Ocean may play a role. Further experiments are planned to clarify the roles of ENSO vis-à-vis those of the MJO.Webinar recording:
https://gmu.webex.com/gmu/ldr.php?RCID=2aa2cd26f8ab42b18eef886e5ce34cd8 -
Dear Colleagues,
Please join us for the February webinar hosted by the WWRP/WCRP/S2S/MJO-Teleconnections sub-project.
Title: Mapping Large-scale Climate Variability to Hydrological Extremes: An Application of the Linear Inverse Model to Subseasonal Prediction
Speaker: Kai-Chih Tseng, GFDLDate: Thursday, February 25, 2021
Time: 10:30am EST | 3:30pm UTCAbstract
The excitation of the Pacific-North American (PNA) teleconnection pattern by the Madden-Julian Oscillation (MJO) has been considered as one of the most important predictability sources on subseasonal timescales over the extratropical Pacific and North America. However, until recently, the interactions between tropical heating and other extratropical modes and their relationships to subseasonal prediction have received comparatively little attention. In this study, a linear inverse model (LIM) is applied to examine the tropical-extratropical interactions. The LIM provides a means of calculating the response of a dynamical system to a small forcing by constructing a linear operator from the observed covariability statistics of the system. Given the linear assumptions, it is shown that the PNA is one of a few leading modes over the extratropical Pacific that can be strongly driven by tropical convection while other extratropical modes present at most a weak interaction with tropical convection. In the second part of this study, a two-step linear regression is introduced which leverages a LIM and large-scale climate variability to the prediction of hydrological extremes (e.g. atmospheric rivers) on subseasonal timescales. Consistent with the findings of the first part, most of the predictable signals on subseasonal timescales are determined by the dynamics of MJO-PNA teleconnection while other extratropical modes are important only at the shortest forecast leads.Webinar recording:
https://gmu.webex.com/gmu/ldr.php?RCID=48afbbc7b5324ac9b40ebfc1c8a3523c -
Dear Colleagues,
Please join us for the February webinar hosted by the WWRP/WCRP/S2S/MJO-Teleconnections sub-project.
Title: Mapping Large-scale Climate Variability to Hydrological Extremes: An Application of the Linear Inverse Model to Subseasonal Prediction
Speaker: Kai-ChihTseng, GFDLDate: Thursday, February 25, 2021
Time: 10:30am EST | 3:30pm UTCAbstract
The excitation of the Pacific-North American (PNA) teleconnection pattern by the Madden-Julian Oscillation (MJO) has been considered as one of the most important predictability sources on subseasonal timescales over the extratropical Pacific and North America. However, until recently, the interactions between tropical heating and other extratropical modes and their relationships to subseasonal prediction have received comparatively little attention. In this study, a linear inverse model (LIM) is applied to examine the tropical-extratropical interactions. The LIM provides a means of calculating the response of a dynamical system to a small forcing by constructing a linear operator from the observed covariability statistics of the system. Given the linear assumptions, it is shown that the PNA is one of a few leading modes over the extratropical Pacific that can be strongly driven by tropical convection while other extratropical modes present at most a weak interaction with tropical convection. In the second part of this study, a two-step linear regression is introduced which leverages a LIM and large-scale climate variability to the prediction of hydrological extremes (e.g. atmospheric rivers) on subseasonal timescales. Consistent with the findings of the first part, most of the predictable signals on subseasonal timescales are determined by the dynamics of MJO-PNA teleconnection while other extratropical modes are important only at the shortest forecast leads.Webinar recording:
https://gmu.webex.com/gmu/ldr.php?RCID=48afbbc7b5324ac9b40ebfc1c8a3523c
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06 Feb
29 Jan
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MJO and Teleconnections 29 Jan, 04:53
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Dear Colleagues,
We are resuming the monthly series of webinars hosted by the WWRP/WCRP/S2S/MJO-Teleconnections sub-project. Please join us for the January webinar.
Title: Intrinsic Uncertainty in the Euro-Atlantic Response to the MJO heating in boreal winter: Ongoing Results from ECMWF Re-Forecasts
Speaker: David Straus, George Mason UniversityDate: Thursday, January 28, 2021
Time: 10:30am EST | 3:30pm UTCAbstract
While the Euro-Atlantic response to the MJO has been well studied in reanalysis and a hierarchy of models, a factor that is often overlooked is the uncertainty in the response due to the intrinsic variability in the full diabatic heating during even a single phase of the MJO.
We examine the heating variability within large (51-member) ensembles of boreal winter reforecasts from the ECMWF model, focusing on forecasts initialized in phases 2 and 3 of the MJO (with heating anomalies located over the Indian Ocean). Results will be shown from new experimental reforecasts in which all the ensemble members utilize identical initial conditions, with the only difference between ensemble members arising from the application of stochastic physics in the target Indian Ocean region. (The stochastic physics is turned off outside the target region.)
The resulting uncertainty (ensemble spread) in the Euro-Atlantic response during the first few weeks of the forecasts is also examined, as well as some discussion of ongoing work to link the response uncertainties to those in the heating. The Euro-Atlantic response is seen to be similar to the traditional MJO response early in the forecast (MJO phases 2/3 leading to the NAO+ regime). However, later on in the forecast variability in the heating over the Pacific Ocean may play a role. Further experiments are planned to clarify the roles of ENSO vis-à-vis those of the MJO.Webinar recording:
Webex meeting recording: S2S MJO-Teleconnections Monthly Webinar-20210128 1535-1
https://gmu.webex.com/gmu/ldr.php?RCID=2aa2cd26f8ab42b18eef886e5ce34cd8
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27 Jan
04 Dec 2020
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Machine Learning 04 Dec, 00:37 2020
01 Dec 2020
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Stratosphere Sub-Project 01 Dec, 01:39 2020
24 Nov 2020
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Stratosphere Sub-Project 24 Nov, 02:13 2020
23 Nov 2020
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Stratosphere Sub-Project 23 Nov, 03:36 2020
30 Oct 2020
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Dear Colleagues,
After another month of hiatus, we are resuming the monthly series of webinars hosted by the WWRP/WCRP/S2S/MJO-Teleconnections sub-project. Please join us for the October webinar.
Title: Understanding tropical-midlatitude interactions: metrics, dynamical processes, and future change
Speaker: Jiabao Wang, School of Marine and Atmospheric Sciences, Stony Brook UniversityDate: Thursday, October 29, 2020
Time: 1pm EDT | 5pm UTC
AbstractTropical convections impact remotely on the midlatitude weather events (e.g., precipitation extremes over California) by forcing changes in circulation patterns. These tropical-midlatitude interactions are particularly important to be accurately simulated and predicted on subseasonal timescales since many management decisions fall within this time range. The Madden-Julian oscillation (MJO) is a unique type of organized tropical convection varying on subseasonal timescales and is recognized as an important source of subseasonal predictability for midlatitude weather phenomena. Better understanding of the MJO-midlatitude interactions is important in improving the simulation, prediction, and the understanding of future changes in MJO associated weather events.
As a joint activity between the WGNE MJO Task Force and WMO S2S teleconnection subproject, we developed a set of standardized diagnostics and metrics to characterize the MJO teleconnections and to understand the associated key dynamical processes (Wang et al. 2020a, b). In this talk, application of these diagnostics to CMIP5 and CMIP6 models will be presented. We will discuss the sensitivity of MJO teleconnections to MJO and basic state representations in models and sources of teleconnection biases. Future changes of MJO teleconnections and the underlying mechanisms will also be discussed.
Wang, J., H. Kim, D. Kim, S. A. Henderson, C. Stan, and E. D. Maloney (2020b): MJO teleconnections over the PNA region in climate models. Part II: Impacts of the MJO and basic state, J. Climate, 33, 5081-5101. doi: 10.1175/JCLI-D-19-0865.1.
Wang, J., H. Kim, D. Kim, S. A. Henderson, C. Stan, and E. D. Maloney (2020a): MJO teleconnections over the PNA region in climate models. Part I: Performance- and process-based skill metrics, J. Climate, 33, 1051-1067. doi: 10.1175/JCLI-D-19-0253.1.
To participate send and email to subseasonal_to_seasonal_prediction_mjo_tel.
Webinar recording:
S2S MJO-Teleconnections Webinar-20201029 1703-1
https://gmu.webex.com/recordingservice/sites/gmu/recording/playback/4011e1ce5a8b49149c295c2382f2159f
22 Oct 2020
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MJO and Teleconnections 22 Oct, 23:44 2020
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Dear Colleagues,
After another month of hiatus, we are resuming the monthly series of webinars hosted by the WWRP/WCRP/S2S/MJO-Teleconnections sub-project. Please join us for the October webinar.
Title: Understanding tropical-midlatitude interactions: metrics, dynamical processes, and future change
Speaker: Jiabao Wang, School of Marine and Atmospheric Sciences, Stony Brook UniversityDate: Thursday, October 29, 2020
Time: 1pm EDT | 5pm UTC
AbstractTropical convections impact remotely on the midlatitude weather events (e.g., precipitation extremes over California) by forcing changes in circulation patterns. These tropical-midlatitude interactions are particularly important to be accurately simulated and predicted on subseasonal timescales since many management decisions fall within this time range. The Madden-Julian oscillation (MJO) is a unique type of organized tropical convection varying on subseasonal timescales and is recognized as an important source of subseasonal predictability for midlatitude weather phenomena. Better understanding of the MJO-midlatitude interactions is important in improving the simulation, prediction, and the understanding of future changes in MJO associated weather events.
As a joint activity between the WGNE MJO Task Force and WMO S2S teleconnection subproject, we developed a set of standardized diagnostics and metrics to characterize the MJO teleconnections and to understand the associated key dynamical processes (Wang et al. 2020a, b). In this talk, application of these diagnostics to CMIP5 and CMIP6 models will be presented. We will discuss the sensitivity of MJO teleconnections to MJO and basic state representations in models and sources of teleconnection biases. Future changes of MJO teleconnections and the underlying mechanisms will also be discussed.
Wang, J., H. Kim, D. Kim, S. A. Henderson, C. Stan, and E. D. Maloney (2020b): MJO teleconnections over the PNA region in climate models. Part II: Impacts of the MJO and basic state, J. Climate, 33, 5081-5101. doi: 10.1175/JCLI-D-19-0865.1.
Wang, J., H. Kim, D. Kim, S. A. Henderson, C. Stan, and E. D. Maloney (2020a): MJO teleconnections over the PNA region in climate models. Part I: Performance- and process-based skill metrics, J. Climate, 33, 1051-1067. doi: 10.1175/JCLI-D-19-0253.1.
To participate send and email to subseasonal_to_seasonal_prediction_mjo_tel.
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25 Sep 2020
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Land Sub-Project 25 Sep, 22:59 2020
17 Sep 2020
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Research to Operations (R2O) and S2S forecast and verification products development 17 Sep, 06:05 2020
12 Sep 2020
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Research to Operations (R2O) and S2S forecast and verification products development 12 Sep, 10:05 2020
11 Sep 2020
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S2S Phase-II Ensembles Sub-project 11 Sep, 11:23 2020
28 Aug 2020
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Dear Colleagues,
After a month of hiatus, we are resuming the monthly series of webinars hosted by the WWRP/WCRP/S2S/MJO-Teleconnections sub-project. Please join us for the August webinar.
Title: Impact of MJO propagation and background flow variability on the evolution of the MJO mid-latitude teleconnection
Speaker: Prof. Edmund Chang, School of Marine and Atmospheric Sciences, Stony Brook University
Date: Thursday, August 27, 2020
Time: 1pm EDT | 5pm UTCAbstract
The MJO acts as a tropical heat source to excite Rossby waves that propagate into the mid-latitudes and modulate the mid-latitude circulation and weather. In this talk, using results from idealized model experiments, I will examine how the MJO excited mid-latitude teleconnection may depend on the history of the MJO evolution, as well as how different mid-latitude large-scale background flow may impact the evolution of the MJO mid-latitude teleconnection.To participate send and email to subseasonal_to_seasonal_prediction_mjo_tel.
Webinar recording:
S2S MJO-Teleconnections -20200827 1705-1
https://gmu.webex.com/recordingservice/sites/gmu/recording/playback/569c57769c04466eba33d1d2abf83643 -
Dear Colleagues,
After a month of hiatus, we are resuming the monthly series of webinars hosted by the WWRP/WCRP/S2S/MJO-Teleconnections sub-project. Please join us for the August webinar.
Title: Impact of MJO propagation and background flow variability on the evolution of the MJO mid-latitude teleconnection
Speaker: Prof. Edmund Chang, School of Marine and Atmospheric Sciences, Stony Brook University
Date: Thursday, August 27, 2020
Time: 1pm EDT | 5pm UTC
Abstract
The MJO acts as a tropical heat source to excite Rossby waves that propagate into the mid-latitudes and modulate the mid-latitude circulation and weather. In this talk, using results from idealized model experiments, I will examine how the MJO excited mid-latitude teleconnection may depend on the history of the MJO evolution, as well as how different mid-latitude large-scale background flow may impact the evolution of the MJO mid-latitude teleconnection.
To participate send and email to subseasonal_to_seasonal_prediction_mjo_tel.
Webinar recording:
S2S MJO-Teleconnections -20200827 1705-1
https://gmu.webex.com/recordingservice/sites/gmu/recording/playback/569c57769c04466eba33d1d2abf83643
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24 Aug 2020
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WGNE_S2S_GAW_Aerosol_Project_2019.pdf
12 Aug 2020
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Research to Operations (R2O) and S2S forecast and verification products development 12 Aug, 11:08 2020
Dear Colleagues,
After a month of hiatus, we are resuming the monthly series of webinars hosted by the WWRP/WCRP/S2S/MJO-Teleconnections sub-project. Please join us for the August webinar.
Title: Impact of MJO propagation and background flow variability on the evolution of the MJO mid-latitude teleconnection
Speaker: Prof. Edmund Chang, School of Marine and Atmospheric Sciences, Stony Brook University
Date: Thursday, August 27, 2020
Time: 1pm EDT | 5pm UTC
Abstract
The MJO acts as a tropical heat source to excite Rossby waves that propagate into the mid-latitudes and modulate the mid-latitude circulation and weather. In this talk, using results from idealized model experiments, I will examine how the MJO excited mid-latitude teleconnection may depend on the history of the MJO evolution, as well as how different mid-latitude large-scale background flow may impact the evolution of the MJO mid-latitude teleconnection.
To participate send and email to subseasonal_to_seasonal_prediction_mjo_tel.
Webinar recording:
https://gmu.webex.com/recordingservice/sites/gmu/recording/playback/569c57769c04466eba33d1d2abf83643