2.10.4. Time zone adjustments

You can use the OUTZONE setting to control the output time zone that defines the hours in the output files. The one constraint on this setting is that it must be consistent with the time zone of the meteorology files. These files are used only when processing on-road mobile sources with MOVES/MOBILE6 (optional), processing elevated point sources for the CMAQ-based approach (required), or processing biogenic emissions with SMOKE BEIS2 or BEIS3 (required). The time zones must be consistent among all source categories processed, so if one source category depends on the meteorology file, then all source categories must be processed with the same OUTZONE setting.

Temporal compares the OUTZONE value with the time zone of the source, which was set in Smkinven (see Section 2.9.14, “Assign country codes, years, and time zones”) based on the county. Additionally, it assesses and accounts for whether the date being processed falls within the range of Daylight Savings Time, and whether the county of the source uses Daylight Savings Time. Temporal uses the COSTCY file to determine which counties use Daylight Savings Time and which do not; for example, the state of Arizona does not use it. Using these pieces of information, Temporal interprets the diurnal profiles assuming that they are local profiles in order to map the correct adjustment to the correct output hour in the output time zone. Temporal also uses the time zone of the source and the output time zone to determine the correct hour for switching from one month to the next and from one day of the week to the next.

Table 2.8, “Example OUTZONE settings and their associated time zones” lists a sampling of OUTZONE settings and the time zones that they represent. Note that SMOKE expects OUTZONE to be set as a positive number for time zones in the Western Hemisphere, although standard notation would list these as negative values. For example, Eastern Standard Time is listed in this table as -5:00 hours from GMT, but OUTZONE for EST in SMOKE is 5. One result of this implementation is that SMOKE does not work perfectly for time zones east of GMT.

Table 2.8. Example OUTZONE settings and their associated time zones

OUTZONE GMT Time zone Description
0 +0:00 GMT Greenwich Mean Time (also known as Zulu time)
4 -4:00 AST Atlantic Standard Time
5 -5:00 EST Eastern Standard Time
6 -6:00 CST Central Standard Time
7 -7:00 MST Mountain Standard Time
8 -8:00 PST Pacific Standard Time
9 -9:00 YST Yukon Standard Time
10 -10:00 HST Hawaiian Standard Time
10 -10:00 CAT Central Alaska Time
11 -11:00 NT Nome Time