2.3.3 Source Region Perturbations
In HTAP1 (HTAP, 2010), a set of 4 rectangular regions approximating North America,
Europe, South Asia, and East Asia was used for the model perturbations studies. In HTAP2, a
two-tiered system of regions has been defined primarily along national boundaries. The first
tier consists of the 16 regions and the second tier consists of 60 sub-regions. These regions
provide a common set of possible source and/or receptor regions for all experiments.
The regions are described on the HTAP WIKI (see Annex 1) and in Annex 4.
Masks in netCDF format (outputNC_20130411_1550.rar) are also provided on the HTAP
WIKI under Work Package 2.1. We note that the dataset has a 'reversed' projection
compared to the HTAP emissions, (longitudes and latitudes starting South instead of
North). This should not be a problem if the software correctly uses attribute information.

Figure 4: The 16 Tier 1 regions (up) and 60 Tier 2 regions (bottom) defined for HTAP2.

After the global and methane perturbations, the next priorities are perturbations by Tier 1
regions. Six of the Tier 1 regions have been designated as higher priority than the others.
These are: North America (NAM), Europe (EUR), South Asia (SAS), East Asia (EAS),
Middle East (MDE), and Russia/Belarus/Ukraine (RBU).
With the BASE and GLOALL results and the results from perturbing all anthropogenic
emissions in one other region (e.g. NAMALL for North America), we can calculate the
following metric, labeled the Response to Extra-Regional Emission Reductions (RERER).
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Table A.4.1: HTAP2 regions
Tier 1

Tier 2

01

GLO*

World

02

OCN

Nonarctic/Antarctic
Ocean

03

NAM*

US+Canada (upto
66 N; polar circle)

04

EUR*

Western + Eastern
EU+Turkey (upto
66 N polar circle)

05

SAS*

06

EAS*

South Asia: India,
Nepal, Pakistan,
Afghanistan,
Bangadesh, Sri
Lanka
East Asia: China,
Korea, Japan

07

SEA

South East Asia

08

PAN

Pacific, Australia+
New Zealand

09

NAF

10

SAF

Northern
Africa+Sahara+Sah
el
Sub Saharan/sub
Sahel Africa

Remark

020 Baltic Sea
021 North Atlantic
022 South Atlantic
023 North Pacific
024 South Pacific
025 Indian Ocean
026 Hudson Bay
027 Mediterranean Sea
028 Black and Caspian Sea
031 NE US
032 SE US
033 NW US
034 SW US
035 E. Canada
036 W. Canada + Alaska up to 66 N.
041 NW Europe
042 SW Europe (France follows province
borders at ca. 46 N).
043 Eastern Europe
044 Greece+Turkey+Cyprus
051 North India +Nepal +Bangladesh
+Afghanistan +Pakistan (ex. Himalaya)
052 South India+Sri Lanka
053 Indian Himalaya
061 North East China
062 South East China
063 West China +Mongolia (excl.
Himalaya)
064 North/South Korea
065 Japan
066 China/Tibet Himalaya
071 Indonesia+Malaysia+Singapore
072 Thailand+Myanmar+Vietnam
081 Pacific
082 Australia
083 New Zealand
091 Egypt
092 Rest of Northern Africa
093 Sahel
101 West and Central Africa: Côte
d’Ivoire, Angola, Benin, Burkina
Faso, Cameroon, Cape Verde, Chad,
Congo Brazzaville, Democratic
Republic of Congo, Equatorial
Guinea, Gambia, Ghana, Guinea,
Guinea Bissau, Liberia, Mali, Niger,
Nigeria, Senegal, Sierra Leone and
Togo (excluding Sahel)
102 East Africa: Burundi, Djibouti, Eritrea,
Ethiopia, Kenya, Sudan, Rwanda,
Uganda, Somalia and Tanzania.
103 Southern Africa: Angola, Botswana,
Lesotho, Madagascar, Malawi,

43

Not provided as
separate mask
150 Arctic seas are
included in the
Arctic receptor
region
160 Antartic seas are
included in Antartic
receptor as Southern
Ocean
Division along state
lines. Emissions
North of 66 N are
marginal.

Himalaya defined as
regions above 1500
m altitude
Himalaya defined as
regions above 1500
m altitude

Sahel identified as
important dust
source region.
Parts of these
countries
included in
Sahel region.

Mauritius, Mozambique, Namibia,
South Africa, Swaziland, Tanzania,
Zambia, and Zimbabwe
111 Lebanon, Israel, Jordan, Syria.
112 Saudi Arabia; Yemen; Oman;
Emirates, Quatar, Bahrein.
113 Iran, Iraq
121 Mexico
122 Central America
123 Caribbean
124 Guyanas, Columbia, Venezuela

11

MDE*

Middle East: S.
Arabia, Oman,
etc, Iran, Iraq

12

MCA

13

SAM

Mexico, Central
America,
Caribbean,
Guyanas,
Venezuela,
Columbia
S. America

14

RBU*

Russia, Belarussia,
Ukraine

15

CAS

Central Asia

16

NPO

Arctic Circle (North
of 66 N)+Greenland

150 Arctic (includes ocean and all of
Greenland)

17

SPO

Antarctic

160 Antarctic
161 Southern Ocean, south of 60S

131 South Brazil
132 Rest of Brazil
133 Uruguay, Paraguay, Argentina, Chile
134 Peru, Ecuador
141 Russia West
142 Russia East
143 Belarussia+Ukraine
151 Uzbekistan, Kazakhstan, Kyrgyzstan,
Tajikistan, Turkmenistan

Pamir mountains not
included in Himalaya
Defined as Tier 1;
but mainly relevant
as receptor
Defined as Tier 1;
but mainly relevant
as receptor

*Regions in bold characters defined as priority regions for TF HTAP Phase 2 simulations.

44