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Past MMM Events

Sharon SessionsDepartment of Physics, New Mexico TechSocorro, New Mexico

Tropical convection is difficult to understand and even more difficult to predict, in part because of the interplay between the convection itself and the large scale circulations.  Predictability is possible, however, if the  scales of convective disturbances are large enough that they are influenced by voriticity anomalies in the environment.  Ooyama, in 1982, discussed this idea in the context of mature tropical cyclones, in a process he refered to as "cooperative intensification".  Recently, Raymond et al. (2015) revisted Ooyama's ideas and addressed the question of whether other less extreme types of tropical disturbances could be a response to a nonlinear form of "balanced dynamics".  If so, they argued that these types of disturbances would have potential for predictability (and therefore would also be parameterizable).  In terms of time scales, disturbances which occur on scales longer than the time to establish balance, are candidates for predictability based on the potential for moist convection to evolve as a balanced response to large scale vorticity anomalies.  

In this talk, I'll revisit some of Ooyama's and Raymond's ideas regarding balance dynamics, and discuss how we would look for signatures of balanced dynamics in convective systems.  I'll also discuss the mechanism by which a vorticity anomaly can modulate and strengthen a developing convective system, and address the question of whether the Madden-Julian Oscillation is a candidate for a convective disturbance under the influence of balanced dynamics.  Finally, I discuss how these concepts can potentially be used to evaluate and diagnose global models that have varying degrees of skill in simulating tropical disturbances (and the MJO in particular).  

Special Wednesday Date--Rescheduled from 18 May 2017 Due to Weather

Wednesday, 24 May 2017, 3:30 PMRefreshments 3:15 PM NCAR--Foothills Laboratory 3450 Mitchell Lane Bldg. 2, Main Auditorium, Room 1022 

 

 

Building:
Room Number: 
1022
Type of event:
Will this event be webcast to the public by NCAR|UCAR?: 
Calendar Timing: 
Thursday, May 25, 2017 - 3:30am to 4:30am

Sharon Sessions
Department of Physics, New Mexico Tech
Socorro, New Mexico

Tropical convection is difficult to understand and even more difficult to predict, in part because of the interplay between the convection itself and the large scale circulations.  Predictability is possible, however, if the  scales of convective disturbances are large enough that they are influenced by voriticity anomalies in the environment.  Ooyama, in 1982, discussed this idea in the context of mature tropical cyclones, in a process he refered to as "cooperative intensification".  Recently, Raymond et al. (2015) revisted Ooyama's ideas and addressed the question of whether other less extreme types of tropical disturbances could be a response to a nonlinear form of "balanced dynamics".  If so, they argued that these types of disturbances would have potential for predictability (and therefore would also be parameterizable).  In terms of time scales, disturbances which occur on scales longer than the time to establish balance, are candidates for predictability based on the potential for moist convection to evolve as a balanced response to large scale vorticity anomalies.  

In this talk, I'll revisit some of Ooyama's and Raymond's ideas regarding balance dynamics, and discuss how we would look for signatures of balanced dynamics in convective systems.  I'll also discuss the mechanism by which a vorticity anomaly can modulate and strengthen a developing convective system, and address the question of whether the Madden-Julian Oscillation is a candidate for a convective disturbance under the influence of balanced dynamics.  Finally, I discuss how these concepts can potentially be used to evaluate and diagnose global models that have varying degrees of skill in simulating tropical disturbances (and the MJO in particular).  

Special Wednesday Date--Rescheduled from 18 May 2017 Due to Weather

Wednesday, 24 May 2017, 3:30 PM
Refreshments 3:15 PM
NCAR--Foothills Laboratory
3450 Mitchell Lane
Bldg. 2, Main Auditorium, Room 1022 

 

 

First Name: 
Bobbie
Last Name: 
Weaver
Phone Extension (4 digits): 
8946
Email: 
weaver@ucar.edu
Building:
Room Number: 
1022
Host lab/program/group:
Type of event:
Calendar Timing: 
Wednesday, May 24, 2017 - 3:30pm to 4:30pm

Anders SivleNorwegian Meteorological InstituteOslo, Norway 

Different people in different occupations depend on weather forecasts to plan their work and recreational schedules. People with no expertise in meteorology frequently interpret weather forecasts and uncertainty information. These non-experts apply their prior knowledge and experiences in a variety of fields to synthesize different types of information to interpret forecasts. In this PhD study, situations of typical users were simulated when examining how different user groups interpret, integrate, and use information from an online weather report (www.Yr.no) in their everyday decision-making. First, qualitative interviews of twenty-one Norwegians (farmers, exterior painters, tour guides, teachers and students) were conducted. Second, sixteen students participated in an eye-tracking study.

The study found that nuances such as color and the number of drops were important in the interpretations of the weather symbols and forecast uncertainty, which were sometimes interpreted differently than intended by the forecast provider. Prior knowledge and the integration of information from different representations affected the participants’ interpretations. The decision-making process influenced the selections of representations in different situations; their selection was dependent on the importance of the envisaged activity and the weather conditions for the day. Additionally, in situations in which the participants had a lack of experiences, this lack provides a possible explanation for why part of the information was occasionally not understood and used.

Some implications of the findings for communication and future research will be discussed in the presentation. For example, it appears that some users should be supported to facilitate the interpretation and use of information in situations where they lack experiences. One possibility to support persons that lack experiences and have low situation awareness might be to provide consequences and impacts of forecast weather. 

Thursday, 8 June 2017, 3:30 PM Refreshments 3:15 PM NCAR-Foothills Laboratory 3450 Mitchell Lane (Location Change) Bldg. 2, Room 1001

Building:
Room Number: 
1001 (Please note location change)
Type of event:
Will this event be webcast to the public by NCAR|UCAR?: 
Calendar Timing: 
Friday, June 9, 2017 - 3:30am to 4:30am

Anders Sivle
Norwegian Meteorological Institute
Oslo, Norway 

Different people in different occupations depend on weather forecasts to plan their work and recreational schedules. People with no expertise in meteorology frequently interpret weather forecasts and uncertainty information. These non-experts apply their prior knowledge and experiences in a variety of fields to synthesize different types of information to interpret forecasts. In this PhD study, situations of typical users were simulated when examining how different user groups interpret, integrate, and use information from an online weather report (www.Yr.no) in their everyday decision-making. First, qualitative interviews of twenty-one Norwegians (farmers, exterior painters, tour guides, teachers and students) were conducted. Second, sixteen students participated in an eye-tracking study.

The study found that nuances such as color and the number of drops were important in the interpretations of the weather symbols and forecast uncertainty, which were sometimes interpreted differently than intended by the forecast provider. Prior knowledge and the integration of information from different representations affected the participants’ interpretations. The decision-making process influenced the selections of representations in different situations; their selection was dependent on the importance of the envisaged activity and the weather conditions for the day. Additionally, in situations in which the participants had a lack of experiences, this lack provides a possible explanation for why part of the information was occasionally not understood and used.

Some implications of the findings for communication and future research will be discussed in the presentation. For example, it appears that some users should be supported to facilitate the interpretation and use of information in situations where they lack experiences. One possibility to support persons that lack experiences and have low situation awareness might be to provide consequences and impacts of forecast weather. 

Thursday, 8 June 2017, 3:30 PM
Refreshments 3:15 PM
NCAR-Foothills Laboratory
3450 Mitchell Lane
(Location Change) Bldg. 2, Room 1001

First Name: 
Bobbie
Last Name: 
Weaver
Phone Extension (4 digits): 
8946
Email: 
weaver@ucar.edu
Building:
Room Number: 
1001 (Please note location change)
Host lab/program/group:
Type of event:
Calendar Timing: 
Thursday, June 8, 2017 - 3:30pm to 4:30pm

Sharon Sessions Department of Physics, New Mexico Tech Socorro, New Mexico 

Tropical convection is difficult to understand and even more difficult to predict, in part because of the interplay between the convection itself and the large scale circulations.  Predictability is possible, however, if the  scales of convective disturbances are large enough that they are influenced by voriticity anomalies in the environment.  Ooyama, in 1982, discussed this idea in the context of mature tropical cyclones, in a process he refered to as "cooperative intensification".  Recently, Raymond et al. (2015) revisted Ooyama's ideas and addressed the question of whether other less extreme types of tropical disturbances could be a response to a nonlinear form of "balanced dynamics".  If so, they argued that these types of disturbances would have potential for predictability (and therefore would also be parameterizable).  In terms of time scales, disturbances which occur on scales longer than the time to establish balance, are candidates for predictability based on the potential for moist convection to evolve as a balanced response to large scale vorticity anomalies.   In this talk, I'll revisit some of Ooyama's and Raymond's ideas regarding balance dynamics, and discuss how we would look for signatures of balanced dynamics in convective systems.  I'll also discuss the mechanism by which a vorticity anomaly can modulate and strengthen a developing convective system, and address the question of whether the Madden-Julian Oscillation is a candidate for a convective disturbance under the influence of balanced dynamics.  Finally, I discuss how these concepts can potentially be used to evaluate and diagnose global models that have varying degrees of skill in simulating tropical disturbances (and the MJO in particular).  

Thursday, 18 May 2017, 3:30 PMRefreshments 3:15 PMNCAR-Foothills Laboratory3450 Mitchell LaneBldg. 2, Main Auditorium, Room 1022 

Building:
Room Number: 
1022
Type of event:
Will this event be webcast to the public by NCAR|UCAR?: 
Calendar Timing: 
Friday, May 19, 2017 - 3:30am to 4:30am

Sharon Sessions
Department of Physics, New Mexico Tech
Socorro, New Mexico 

Tropical convection is difficult to understand and even more difficult to predict, in part because of the interplay between the convection itself and the large scale circulations.  Predictability is possible, however, if the  scales of convective disturbances are large enough that they are influenced by voriticity anomalies in the environment.  Ooyama, in 1982, discussed this idea in the context of mature tropical cyclones, in a process he refered to as "cooperative intensification".  Recently, Raymond et al. (2015) revisted Ooyama's ideas and addressed the question of whether other less extreme types of tropical disturbances could be a response to a nonlinear form of "balanced dynamics".  If so, they argued that these types of disturbances would have potential for predictability (and therefore would also be parameterizable).  In terms of time scales, disturbances which occur on scales longer than the time to establish balance, are candidates for predictability based on the potential for moist convection to evolve as a balanced response to large scale vorticity anomalies.  

In this talk, I'll revisit some of Ooyama's and Raymond's ideas regarding balance dynamics, and discuss how we would look for signatures of balanced dynamics in convective systems.  I'll also discuss the mechanism by which a vorticity anomaly can modulate and strengthen a developing convective system, and address the question of whether the Madden-Julian Oscillation is a candidate for a convective disturbance under the influence of balanced dynamics.  Finally, I discuss how these concepts can potentially be used to evaluate and diagnose global models that have varying degrees of skill in simulating tropical disturbances (and the MJO in particular).  

Thursday, 18 May 2017, 3:30 PM
Refreshments 3:15 PM
NCAR-Foothills Laboratory
3450 Mitchell Lane
Bldg. 2, Main Auditorium, Room 1022 

First Name: 
Bobbie
Last Name: 
Weaver
Phone Extension (4 digits): 
8946
Email: 
weaver@ucar.edu
Building:
Room Number: 
1022
Host lab/program/group:
Type of event:
Calendar Timing: 
Thursday, May 18, 2017 - 3:30pm to 4:30pm

Joseph Sedlar Swedish Meteorological and Hydrological Institute Norrkoping, Sweden 

Over the Arctic, persistent cloudiness and variable boundary layer structure pose serious problems for accurate numerical simulation of these phenomena. The issue is generally compounded by insufficient observational data, which are necessary for understanding processes and improvement of physical parameterizations.

In this presentation, observations spanning a broad range of spatial and temporal scales, including cloud-turbulence scales and up to pan-Arctic scales, are explored. Statistics and decomposition techniques are applied to understand the role of cloud-driven dynamics versus larger meso- and synoptic-scale forcings during the Arctic summer, to quantify their relative importance on the lower tropospheric structure. A particular focus of this presentation is devoted to highlighting the mechanisms supporting the decoupled nature between near-surface turbulence and mixed-phase cloud-driven mixing. The impact of poleward advection on components of the atmospheric energy budget is also analyzed.

Special Day and Time:

Tuesday, 18 April 2017, 1:30 PMRefreshments 1:15 PM NCAR-Foothills Laboratory 3450 Mitchell Lane Bldg. 2, Main Auditorium, Room 1022

Building:
Room Number: 
1022
Type of event:
Will this event be webcast to the public by NCAR|UCAR?: 
Calendar Timing: 
Wednesday, April 19, 2017 - 1:30am to 2:30am

Joseph Sedlar
Swedish Meteorological and Hydrological Institute
Norrkoping, Sweden 

Over the Arctic, persistent cloudiness and variable boundary layer structure pose serious problems for accurate numerical simulation of these phenomena. The issue is generally compounded by insufficient observational data, which are necessary for understanding processes and improvement of physical parameterizations.

In this presentation, observations spanning a broad range of spatial and temporal scales, including cloud-turbulence scales and up to pan-Arctic scales, are explored. Statistics and decomposition techniques are applied to understand the role of cloud-driven dynamics versus larger meso- and synoptic-scale forcings during the Arctic summer, to quantify their relative importance on the lower tropospheric structure. A particular focus of this presentation is devoted to highlighting the mechanisms supporting the decoupled nature between near-surface turbulence and mixed-phase cloud-driven mixing. The impact of poleward advection on components of the atmospheric energy budget is also analyzed.

Special Day and Time:

Tuesday, 18 April 2017, 1:30 PM
Refreshments 1:15 PM
NCAR-Foothills Laboratory
3450 Mitchell Lane
Bldg. 2, Main Auditorium, Room 1022

First Name: 
Bobbie
Last Name: 
Weaver
Phone Extension (4 digits): 
8946
Email: 
weaver@ucar.edu
Building:
Room Number: 
1022
Host lab/program/group:
Type of event:
Calendar Timing: 
Tuesday, April 18, 2017 - 1:30pm to 2:30pm

Mathew Stiller-ReeveClimate and The Bjerknes Centre for Climate ResearchBergen, Norway

If we want climate services to produce useable information for users, then the way scientists and users define events need to be comparable. In this talk, I will present some novel yet simple methods to compare beliefs of timing of recurrent climatic events with empirical evidence from multiple historical time series. We test the methods by applying them to the onset date of the monsoon in Bangladesh, where several scientific monsoon definitions can be applied. Time series from eight different scientific monsoon definitions in six regions are compared with respondent beliefs from a previously completed survey concerning the monsoon onset.

Beliefs about the timing of the monsoon onset are represented probabilistically for each respondent by constructing a probability mass function from elicited responses about the earliest, normal, and latest dates for the event. We use these dates to construct a circular modified triangular distribution (CMTD). These CMTD distributions are then compared to the historical time series using two approaches: likelihood scores, and the mean and standard deviation of time series of dates simulated from each belief distribution.

This work has developed from my previous PhD research and the more recent TRACKS project (Transforming Climate Knowledge with and for Society) funded by the Norwegian Research Council. The methods are initially based on the monsoon onset, but I would like to discuss the possibility of applying them to other meteorological or climatological events.

Thursday, 6 April 2017, 3:30 PMRefreshments 3:15 PMNCAR-Foothills Laboratory3450 Mitchell LaneBldg. 2, Main Auditorium, Room 1022

Building:
Room Number: 
1022
Type of event:
Will this event be webcast to the public by NCAR|UCAR?: 
Calendar Timing: 
Friday, April 7, 2017 - 3:30am to 4:30am

Mathew Stiller-Reeve
Climate and The Bjerknes Centre for Climate Research
Bergen, Norway

If we want climate services to produce useable information for users, then the way scientists and users define events need to be comparable. In this talk, I will present some novel yet simple methods to compare beliefs of timing of recurrent climatic events with empirical evidence from multiple historical time series. We test the methods by applying them to the onset date of the monsoon in Bangladesh, where several scientific monsoon definitions can be applied. Time series from eight different scientific monsoon definitions in six regions are compared with respondent beliefs from a previously completed survey concerning the monsoon onset.

Beliefs about the timing of the monsoon onset are represented probabilistically for each respondent by constructing a probability mass function from elicited responses about the earliest, normal, and latest dates for the event. We use these dates to construct a circular modified triangular distribution (CMTD). These CMTD distributions are then compared to the historical time series using two approaches: likelihood scores, and the mean and standard deviation of time series of dates simulated from each belief distribution.

This work has developed from my previous PhD research and the more recent TRACKS project (Transforming Climate Knowledge with and for Society) funded by the Norwegian Research Council. The methods are initially based on the monsoon onset, but I would like to discuss the possibility of applying them to other meteorological or climatological events.

Thursday, 6 April 2017, 3:30 PM
Refreshments 3:15 PM
NCAR-Foothills Laboratory
3450 Mitchell Lane
Bldg. 2, Main Auditorium, Room 1022

First Name: 
Bobbie
Last Name: 
Weaver
Phone Extension (4 digits): 
8946
Email: 
weaver@ucar.edu
Building:
Room Number: 
1022
Host lab/program/group:
Type of event:
Calendar Timing: 
Thursday, April 6, 2017 - 3:30pm to 4:30pm

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