N and S, especially along eastern and western
margins near continents.Equatorial/Tropical Oceans. Region of westward-flowing warm equatorial currents; Intertropical Convergence Zone; beginning of Hadley cells; marked by high evaporation with consequently heavy rainfall and large amounts of moisture in the atmosphere; global maximum of atmospheric water vapor content.
Tropical Cyclone Spawning Areas. Regions of poleward extent of the Intertropical Convergence Zone, about 10-15 N and S, especially along eastern and western
margins near continents.
Central Gyres. Subtropical central oceans; regions of atmospheric high pressure cells with little precipitation; characterized by high salinity and fairly warm temperatures; areally the dominant feature of ocean circulation; relatively uniform over large regions; principal climate drivers for the midlatitude continents.
Western Boundary Currents. Subtropical to midlatitude; poleward turn of warm equatorial currents; currents tend to be compressed, long, narrow, not much surface area; considerable cloudiness; much warmer than land areas immediately to west, especially in winter; maximum latent heat input to atmosphere. (Gulf Stream; Brazil Current; Kuroshio Current; Agulhas Current; East Australian Current).
Eastern Boundary Currents. Subtropical latitudes; slightly equatorward in the southern hemisphere, northward to about 35N in the eastern North Pacific; region
of stratus development due to weak upwelling of cold currents as they turn along the continents toward the equator; dry, especially in the southern hemisphere,
where annual precipitation averages less than 100 mm. (California Current; Peru (Humboldt) Current; Canaries Current, Benguela Current).
Eastern Margins of the Gyres. Transitional areas between the central gyres and the cold eastern boundary currents; slow equatorward drift; regions of stratocumulus (transition to marine stratus along the boundary currents).
Mediterranean Seas. A true (salt-water) sea completely enclosed by land; large enough to be "oceanic" but restricted ocean dynamics; no central gyre or well-developed boundary currents; semi-arid climate with hot, dry summers, rainy winters; climate less marine, more influenced by adjacent land climate than open ocean areas. (Mediterranean Sea).
High Latitude Ice-Free Seas. General category including seas with differing characteristics; Norwegian Sea is ice free due to warming by the North Atlantic Drift; scene of considerable heat exchange between atmosphere and ocean; Circumpolar Southern Ocean is the connecting area for all world's oceans (only free exchange on globe); energetic, region of strong atmospheric frontal activity.
High Latitude Ocean Ice Edge. The Marginal Ice Zone; possibly the most important category from a climatic point of view due to pronounced positive feedback conditions; however, very difficult logistically to monitor. (Greenland Sea; Bering Sea; Chukchi Sea; Ross Sea).
Semi-Enclosed Seas. Detached from open oceans by island chains, limiting water exchange; limited ocean dynamics; smaller size amplifies changes in adjacent ocean conditions, more apparent atmospheric feedback effects.
Inland Water Bodies. General category of freshwater or brackish water bodies lacking ocean characteristics but large enough to affect climate over adjacent land areas; water budget is sensitive to river flow. (Great Lakes; Lake Titicaca; Black Sea, Baltic Sea; Lake Victoria).
Once the climatologically significant locale categories were identified, several locales were identified for each category, taking terrain, surface cover (e.g., natural vegetation, crops, ice) and patterns of air masses, winds and ocean currents into account to focus on distinct areas within the broader regions.
Finally, the list of potential locales identified by this process was shortened to a list of candidate locales which were to be evaluated by the CETs to determine their suitability in meeting the ARM objectives. Candidate locales were selected for detailed examination on the basis of meeting one or more of the following criteria:
This set of categories was selected to span a broad range of climatic and geographic regimes. In selecting the candidate locales, it was deemed preferable to suggest multiple, approximately equivalent locales within categories of greatest potential interest to ARM, rather than to select one locale from every category. By keeping the list of candidate locales down to a workable size, the CETs could devote their attention to applying detailed criteria, including logistic and synergistic considerations, to the locales of greatest scientific merit. Therefore, based on initial prioritization some categories were not represented in the final list. The locale categories and potential and candidate locales within these categories, are given in Table 3; candidate locales are indicated by check marks (X).
The initial roster of potential and candidate locales was circulated to the ARM Management Team and to members of the Locale Recommendation Team. This list
was also reviewed by the members of the Science Team in their review of a draft version of this report. It was explicitly noted that additional locale categories
and/or candidate locales could be added to the list at any time. Locales which were subsequently added to the original list are also included in Table 3. All
locales were then subjected to examination by each CET. The approximate locations of the candidate locales are shown in Figure 2,
Figure 3, and Figure 4. The illustrated
locale boundaries should not be taken as absolute; the attributes of each locale are more critical to this decision process than are precise locations. Two
candidate locales do not appear on the maps: the Antarctic Plateau, which is the ice-covered heart of the continent and does not include the mountainous areas;
and the Circumpolar Southern Ocean, which stretches from the edge of the continent to approximately 45S latitude.
