Tropical/Northern Hemisphere Teleconnection Patterns from NOAA/Climate Prediction Center
Entry ID: NOAA_NWS_CPC_TNH

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Summary
Abstract: [Source: NOAA Climate Prediction Center, http://www.cpc.ncep.noaa.gov/ ]

The Tropical/ Northern Hemisphere pattern was first classified by Mo and Livezey (1986), and appears as a prominent mode from November-February. The pattern consists of one primary anomaly center over the Gulf of Alaska and a separate anomaly center of opposite sign over the Hudson Bay. A weaker area of anomalies having similar sign to the Gulf of Alaska anomaly extends across Mexico and the extreme southeastern United States. This pattern reflects large-scale changes in both the location and eastward extent of the Pacific jet stream, and also in the strength and position of the climatological mean Hudson Bay Low. Thus, the pattern significantly modulates the flow of marine air into North America, as well as the southward transport of cold Canadian air into the north-central United States.

Pronounced negative phases of the TNH pattern are often observed during December and January when Pacific warm (ENSO) episode conditions are present (Barnston et al. 1991). One recent example of this is the 1994/95 winter season, when mature Pacific warm episode conditions and a strong negative phase of the TNH pattern were present. During this period, the mean Hudson Bay trough was much weaker than normal and shifted northeastward toward the Labrador Sea. Additionally, the Pacific jet stream was much stronger than normal and shifted southward to central California, well south of its climatological mean position in the Pacific Northwest. This flow pattern brought well above-normal temperatures to eastern North America and above-normal rainfall to the southwestern United States.

In contrast, positive phases of the TNH pattern tend to accompany Pacific cold events. An example is the very persistent positive phase of the TNH pattern during 1988/89 -1990/91, which developed in apparent association with the strong 1988/89 Pacific cold event.

Related URL
Link: GET DATA
Description: Access to TNH documentation, graphs and data


Geographic Coverage
 N: 90.0 S: 0.0  E: 180.0  W: -180.0

Data Set Citation
Dataset Originator/Creator: NOAA/NWS/CPC
Dataset Title: Tropical/Northern Hemisphere Teleconnection Pattern
Dataset Series Name: NOAA/NWS/CPC Indices and Forecasts
Dataset Release Date: ongoing
Dataset Release Place: Camp Springs, MD
Dataset Publisher: NOAA National Weather Service, Center for Climate Prediction
Online Resource: http://www.cpc.ncep.noaa.gov/data/teledoc/tnh.shtml


Temporal Coverage
Start Date: 1950-01-01


Location Keywords
OCEAN > ATLANTIC OCEAN
OCEAN > PACIFIC OCEAN > NORTH PACIFIC OCEAN > GULF OF ALASKA
OCEAN > PACIFIC OCEAN > NORTH PACIFIC OCEAN
OCEAN > PACIFIC OCEAN
CONTINENT > NORTH AMERICA
GEOGRAPHIC REGION > NORTHERN HEMISPHERE
GEOGRAPHIC REGION > TROPICS


Data Resolution
Temporal Resolution: daily, monthly, seasonal


Science Keywords
ATMOSPHERE >ALTITUDE >GEOPOTENTIAL HEIGHT    [Definition]
ATMOSPHERE >ATMOSPHERIC PRESSURE >OSCILLATIONS >TROPICAL/NORTHERN HEMISPHERE PATTERN    [Definition]
ATMOSPHERE >ATMOSPHERIC PRESSURE >PRESSURE ANOMALIES    [Definition]
ATMOSPHERE >ATMOSPHERIC WINDS >UPPER LEVEL WINDS    [Definition]
CLIMATE INDICATORS >ATMOSPHERIC/OCEAN INDICATORS >TELECONNECTIONS >EL NINO SOUTHERN OSCILLATION (ENSO)    [Definition]
CLIMATE INDICATORS >ATMOSPHERIC/OCEAN INDICATORS >TELECONNECTIONS >QUASI-BIENNIAL OSCILLATION    [Definition]
CLIMATE INDICATORS >ATMOSPHERIC/OCEAN INDICATORS >TELECONNECTIONS >TROPICAL/NORTHERN HEMISPHERE PATTERN    [Definition]


ISO Topic Category
CLIMATOLOGY/METEOROLOGY/ATMOSPHERE


Keywords
Tropical/Northern Hemisphere Pattern
TNH
climate index
climate indices
forecast indices
atmospheric circulation
climate change
teleconnections


Data Set Progress
IN WORK


Originating Center
NOAA/NWS/CPC


Data Center
Climate Prediction Center, National Centers for Environmental Prediction, National Weather Service, NOAA, U.S. Department of Commerce    [Information]
Data Center URL: http://www.cpc.ncep.noaa.gov/
Dataset ID: Tropical/Northern Hemisphere Pattern

Data Center Personnel
Name: ED O'LENIC
Email: Ed.Olenic at noaa.gov



Distribution
Distribution_Media: online www
Distribution_Format: ascii
Fees: none


Personnel
SCOTT A. RITZ
Role: TECHNICAL CONTACT
Phone: 301-614-5126
Fax: 301-614-5268
Email: Scott.A.Ritz at nasa.gov
Contact Address:
NASA Goddard Space Flight Center
Global Change Master Directory
City: Greenbelt
Province or State: Maryland
Postal Code: 20771
Country: USA


ED O'LENIC
Role: TECHNICAL CONTACT
Email: Ed.Olenic at noaa.gov


Publications/References
Barnston, A.G., and R.E. Livezey, 1987: Classification, seasonality
and persistence of low - frequency atmospheric circulation
patterns. Mon. Wea. Rev., 115, 1083-1126.

Barnston, A.G., R.E. Livezey, and M.S. Halpert, 1991. Modulation of
Southern Oscillation-Northern Hemisphere mid-winter climate
relationships by the QBO. J. of Climate. 4: 203-217.

Mo, K. C., and R. E. Livezey, 1986: Tropical-extratropical
geopotential height teleconnections during the Northern Hemisphere
winter. Mon. Wea. Rev., 114, 2488-2515.

Creation and Review Dates
DIF Creation Date: 2003-02-20
Last DIF Revision Date: 2009-11-05

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