Climate Data and Indices

Objectives

  • Understand the data sources and simulations

  • Know the available climate indices

Data Sources and Simulations

The data for this analysis comes from three long-term simulations produced using the Norwegian Earth System Model (NorESM1-F). These simulations span hundreds of years and include both historical and pre-industrial climate conditions.

  1. Historical Simulation with SLOW Forcing (850-2005 AD): Accounts for low solar variability, transient volcanic activity, and anthropogenic effects.

  2. Historical Simulation with HIGH Forcing (850-2005 AD): Similar to the first but uses high solar variability.

  3. Pre-Industrial Control Simulation (PICNTL): Simulates 1,000 years with constant solar and volcanic forcing, and pre-industrial (1850-level) anthropogenic forcing.

Climate Indices

This repository works with a wide range of climate indices, which are used to study various aspects of climate variability:

  • Global Surface Temperature Indices: glTSann, nhTSann, shTSann

  • Sea Surface Temperature (SST) Indices: amoSSTann, satlSSTann, ensoSSTjfm

  • Sea Ice Concentration (SIC) Indices: nhSICmar, nhSICsep, shSICmar, shSICsep

  • Precipitation Indices: nchinaPRjja, yrvPRjja, ismPRjja

  • Pressure Indices: naoPSLjfm, eapPSLjfm, scpPSLjfm

  • Ocean Circulation Indices: AMOCann, traBO, traBS

A detailed description of each index is provided below.

Default Predictors

These indices provide historical data used to build the model for predicting future conditions:

Atmospheric Pressure:

  • naoPSLjfm: North Atlantic Oscillation (NAO) pressure anomalies (December-February, boreal winter)

  • eapPSLjfm: East Atlantic Pattern (EAP) pressure anomalies (December-February, boreal winter)

  • scpPSLjfm: Scandinavian Pattern (SCP) pressure anomalies (December-February, boreal winter)

  • eurPSLjfm: Euro-Mediterranean Pattern (EU) pressure anomalies (December-February, boreal winter)

Sea Ice Concentration:

  • nhSICmar: Northern Hemisphere Sea Ice Concentration (March)

  • nhSICsep: Northern Hemisphere Sea Ice Concentration (September)

  • shSICmar: Southern Hemisphere Sea Ice Concentration (March)

  • shSICsep: Southern Hemisphere Sea Ice Concentration (September)

  • atlSICmar: Atlantic Sea Ice Concentration (March)

  • atlSICsep: Atlantic Sea Ice Concentration (September)

Ocean Circulation:

  • AMOCann: Atlantic Meridional Overturning Circulation (AMOC) anomaly (annual)

Atmospheric Circulation (November-December-January, boreal winter):

  • stratZ50ndj01: Stratospheric 50 hPa Geopotential Height anomalies (November)

  • stratZ50ndj02: Stratospheric 50 hPa Geopotential Height anomalies (December)

  • stratZ50ndj03: Stratospheric 50 hPa Geopotential Height anomalies (January)

  • stratZ50ndj04: Stratospheric 50 hPa Geopotential Height anomalies (December-January-February)

Ocean Temperatures:

  • amoSSTann: (included as both a predictor and predictand) Annual AMO SST anomaly

  • amoSSTmjjaso: AMO SST anomaly (May-June-July-August-September, boreal summer)

  • amo1, amo2, amo3: These represent additional principal components of the AMO

Other Available Predictors

Variable

Description

glTSann

annual mean global surface temperature (degC)

nhTSann

annual mean northern hemisphere surface temperature (degC)

shTSann

annual mean southern hemisphere surface temperature (degC)

cetTSann

annual mean Central England surface temperature (degC)

amoSSTann

annual mean Atlantic (0-60N; 75W-7.5W) sea surface temperature (SST; degC)

satlSSTann

annual mean South Atlantic (60S-0S; 60W-15E) SST (degC)

ensoSSTjfm

winter (JFM) mean ENSO (Nino3.4 region) SST index (degC)

neurTSjfm

winter (JFM) mean northern Europe surface temperature index (degC)

seurTSjfm

winter (JFM) mean southern Europe surface temperature index (degC)

arcTSann

annual mean Arctic (north of 60N) surface temperature (degC)

nhSICmar

northern hemisphere sea ice concentration (%) for March

nhSICsep

northern hemisphere sea ice concentration (%) for September

shSICmar

southern hemisphere sea ice concentration (%) for March

shSICsep

southern hemisphere sea ice concentration (%) for September

nchinaPRjja

summer (JJA) precipitation over northern China

yrvPRjja

summer (JJA) precipitation over Yangtze River region in China

ismPRjja

summer (JJA) precipitation over Indian Monsoon region in Asia

wnorPRjfm

winter (JFM) precipitation for western Norway

naoPSLjfm

leading principal component (PC1) from North Atlantic sea level pressure

eapPSLjfm

second principal component (PC2) from North Atlantic sea level pressure

scpPSLjfm

third principal component (PC3) from North Atlantic sea level pressure

eurPSLjfm

fourth principal component (PC4) from North Atlantic sea level pressure

solFORC

annual total solar irradiance index (W m-2) (only for shigh and slow simulations)

samPSLann

annular mean Southern annular mode (SAM) pressure index

atlSICmar

March sea ice concentration (%) for the Atlantic sector

atlSICsep

September sea ice concentration (%) for the Atlantic sector

pdoSSTjfm

Pacific Decadal Oscillation (PDO) index as leading PC of North Pacific SST

nppc2SSTjfm

Second PC of North Pacific SST

nppc3SSTjfm

Third PC of North Pacific SST

AMOCann

Annual mean Atlantic meridional overturning circulation (Sv)

traBO

Volume transport (Sv) Barents Opening

traBS

Volume transport (Sv) Bering Strait

traCA

Volume transport (Sv) Canadian Archipelago

traDS

Volume transport (Sv) Denmark Strait

traDP

Volume transport (Sv) Drake Passage

traEC

Volume transport (Sv) English Channel

traEU

Volume transport (Sv) Equatorial Undercurrent

traFSC

Volume transport (Sv) Faroe Shetland Channel

traFB

Volume transport (Sv) Florida - Bahamas

traFS

Volume transport (Sv) Fram Strait

traIFC

Volume transport (Sv) Iceland Faroe Channel

traIT

Volume transport (Sv) Indonesian Throughflow

traMC

Volume transport (Sv) Mozambique Channel

traTLS

Volume transport (Sv) Taiwan and Luzon Straits

traWP

Volume transport (Sv) Windward Passage

alpi

Aleutian Low Pressure Index

mhfATL30

meridional heat flux Atlantic Ocean at 30N

mhfATL45

meridional heat flux Atlantic Ocean at 45N

mhfATL60

meridional heat flux Atlantic Ocean at 60N

mhfIP30

meridional heat flux Indian-Pacific Ocean at 30N

tripol1

annual mean SST index for the tripole 1 Pacific region

tripol2

annual mean SST index for the tripole 2 Pacific region

tripol3

annual mean SST index for the tripole 3 Pacific region

amo1

annual mean SST index for Atlantic Ocean 0-30N

amo2

annual mean SST index for Atlantic Ocean 30-45N

amo3

annual mean SST index for Atlantic Ocean 45-60N

labSSTann

annual mean SST index (degC) over the Labrador Sea

ormenSSTann

annual mean SST index (degC) over the Ormen Lange region

gyreSSTann

annual mean SST index (degC) over the Subpolar Gyre

ginwSSTann

annual mean SST index (degC) over the western Nordic Seas

glomaSSTann

annual mean AMO-index with global mean (excluding the Atlantic) removed

amoSSTmjjaso

extended summer AMO-index

stratZ50ndj01

leading PC for geopotential height at 50 hPa for NH north of 20N

stratZ50ndj02

second PC for geopotential height at 50 hPa for NH north of 20N

stratZ50ndj03

third PC for geopotential height at 50 hPa for NH north of 20N

stratZ50ndj04

fourth PC for geopotential height at 50 hPa for NH north of 20N

Keypoints

  • Data comes from NorESM1-F simulations: SLOW, HIGH, and PICNTL

  • 65 climate indices are available covering temperature, pressure, ocean, and ice

  • Indices can be used as predictors or prediction targets