Seasonal prediction
This presentation is the property of its rightful owner.
Sponsored Links
1 / 21

Seasonal Prediction PowerPoint PPT Presentation


  • 98 Views
  • Uploaded on
  • Presentation posted in: General

Seasonal Prediction. Carl Schreck. El Niño/La Niña. History. Climate Modes. Seasonal Hurricane Prediction. El Niño/La Niña. History. Climate Modes. Users. Emergency Managers Raises public awareness Reinsurance Industry Companies that insure the companies you buy insurance from

Download Presentation

Seasonal Prediction

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Seasonal prediction

Seasonal Prediction

Carl Schreck

El Niño/La Niña

History

Climate Modes


Seasonal hurricane prediction

Seasonal Hurricane Prediction

El Niño/La Niña

History

Climate Modes


Users

Users

  • Emergency Managers

    • Raises public awareness

  • Reinsurance Industry

    • Companies that insure the companies you buy insurance from

    • Risk Prediction Initiative (RPI2.0) is a leader in bringing new forecast methods to the industry

  • Energy Traders

    • Oil and natural gas drilling in the Gulf is vulnerable

    • Futures prices respond to the seasonal forecasts

El Niño/La Niña

History

Climate Modes


History

History

  • Bill Gray (Colorado State University) discovered the basic hurricane ingredients in the 1960s

  • Many of those ingredients can be driven by large scale climate modes

  • Climate modes in winter and springtime can predict hurricane activity for upcoming season

El Niño/La Niña

History

Climate Modes


Gray s seasonal predictors initial

Gray’s Seasonal Predictors (Initial)

  • West African Rainfall

    • Intense rainfall produced stronger easterly waves

  • Sea level pressure anomaly in Caribbean

    • Lower = more activity

  • 200 mb zonal wind anomaly in Caribbean

    • If positive, more vertical wind shear over area, less activity

    • Tended to persist from spring into hurricane season

  • ENSO

    • Warm phase created more wind shear over Atlantic, less TC activity

Landsea and Gray (1992, BAMS)

El Niño/La Niña

History

Climate Modes


Klotzbach gray predictors since 2010

Klotzbach/Gray Predictors (since 2010)

  • January-March Atlantic SST

  • March Atlantic SLP

  • February-March Pacific SLP

  • ECMWF ENSO forecast

El Niño/La Niña

History

Climate Modes


The future of seasonal prediction

The Future of Seasonal Prediction?

  • Physics-based dynamical models are getting better at seasonal prediction

  • Ensembles of these models provide estimate the range of possible outcomes

  • Generally not as good as statistical forecasts…yet

Schemm et al. (2012, CDPW)

El Niño/La Niña

History

Climate Modes


El ni o southern oscillation enso

El Niño–Southern Oscillation (ENSO)

El Niño/La Niña

History

Climate Modes


Characteristics of la ni a

Characteristics of La Niña

  • Anomalous low (high) pressure in the western (eastern) Pacific

  • Stronger than normal trade winds across Pacific

  • Dry (Wet) conditions in the east (west) Pacific

  • Deep thermocline in the west – shallow in the east

El Niño/La Niña

History

Climate Modes

Courtesy of C.C. Hennon, UNC Asheville


Characteristics of el ni o

Characteristics of El Niño

  • Anomalous low (high) pressure in the eastern (western) Pacific

  • Weak or even reversed trade winds across Pacific

  • Dry (Wet) conditions in the west (east) Pacific

  • Deep thermocline in the east – upwelling capped

Courtesy of C.C. Hennon, UNC Asheville

El Niño/La Niña

History

Climate Modes


Determining the phase of enso

Determining the phase of ENSO

x

Darwin

x

Tahiti

  • Southern Oscillation Index (SOI)

    • Tracks the see-saw in pressure between western Pacific/Indian Ocean and central Pacific

    • Uses pressure observations from Tahiti and Darwin, Australia

  • Sea-surface Temperature (SST) based methods

    • Average SST anomalies over various regions of the Pacific

El Niño/La Niña

History

Climate Modes


Impact on hurricanes

Impact on Hurricanes

iri.columbia.edu

El Niño/La Niña

History

Climate Modes


Recent enso conditions

Recent ENSO Conditions

cpc.ncep.noaa.gov

El Niño/La Niña

History

Climate Modes


Enso forecasting

ENSO Forecasting

  • Dynamical Models

    • Starts with the current state of the atmosphere/ocean on a grid

    • Uses physics approx. to predict its evolution

  • Statistical Models

    • Based on current atmospheric and ocean conditions

  • All models struggle during January–May

    • “Spring Barrier”

  • Better forecasts in April through June when conditions are already developing

El Niño/La Niña

History

Climate Modes


Main development region slp sst vws

Main Development Region SLP/SST/VWS

El Niño/La Niña

History

Climate Modes


Atlantic multi decadal oscillation amo

Atlantic Multi-Decadal Oscillation (AMO)

  • Atlantic SSTs vary with a period of 60–80 years

  • Hurricane activity follows a similar pattern

  • Recent warmth is a combination of climate change and the AMO

  • Thought to be driven by the thermohaline circulation, but we don’t know

Trenberth & Shea (2006, GRL)

El Niño/La Niña

History

Climate Modes


Atlantic meridional mode amm

Atlantic Meridional Mode (AMM)

Kossin and Vimont (2007, BAMS)

Genesis locations, SST anomalies (shading) and Shear anomalies (contours)

AMM loading pattern

  • Dipole of SST between the North and South Atlantic

    ≈ TNA – TSA

  • Closely related to the AMO

    • But AMM has a stronger relationship with Hurricane activity

TNA

TSA

El Niño/La Niña

History

Climate Modes


Global n hem s hem temperature

Global/N.Hem./S.Hem. Temperature

data.giss.nasa.gov

  • Hurricane Ingredient: Conditionally unstable atmosphere

    • Warm air rises, but only if it’s warmer than its surroundings

  • Surface temperatures from around the globe get distributed into the atmosphere

  • Key Climate Change Debate:

    • Do Hurricanes respond to Total or Relative changes in SST?

El Niño/La Niña

History

Climate Modes


Solar flux

Solar Flux

  • Sun goes through 11-year cycles in its output

  • These cycles affect surface temperatures

  • Not clear how Solar flux would be a better predictor than temperature

  • But empirical relationships can lead to new discoveries

El Niño/La Niña

History

Climate Modes


Midlatitude teleconnection patterns

Midlatitude Teleconnection Patterns

  • Based on the locations of high and low pressure centers

  • Related to variations in the jet stream

  • Not clear how they affect hurricanes

    • Variations in shear?

    • Downstream variations in the Bermuda High?

Arctic Oscillation (AO)

North Atlantic

Oscillation (NAO)

Pacific–North American

Pattern (PNA)

East Pacific/North Pacific

Oscillation (EPO)

cpc.ncep.noaa.gov

El Niño/La Niña

History

Climate Modes


Summary

Summary

Ingredients

Climate Modes

Deep Warm Ocean Layer

MDR Sea Surface Temperature

MDR Sea-Level Pressure

Conditionally Unstable

Atmosphere

MDR Vertical Wind Shear

Moist Mid-Troposphere

El Niño/La Niña

Atlantic Multi-decadal

Oscillation (AMO)

Pre-existing Convection

Atlantic Meridional

Mode (AMM)

Weak Vertical Shear

Cyclonic Low-Level

Vorticity

Global/Hemispheric

Surface Temperature

El Niño/La Niña

History

Climate Modes


  • Login