Potential annual (January-December) and summertime (June-August) regional time trends and increasingly extreme and / or variable values of Palmer-based drought indices were investigated over the contiguous United States (US) between 1895 and the present. Although there has been no significant change in the annual or summertime Palmer Drought Severity Index (PDSI), Palmer Hydrological Drought Index (PHDI), or Palmer Modified Drought Index (PMDI) for the contiguous US over this time frame, there is clear evidence of decreasing drought conditions in the eastern US (northeast, east north central, central, and southeast climate zones) and increasing drought conditions in the west climate region (California and Nevada). No significant time trends were found in the annual or summertime PDSI, PHDI, and PMDI for the spring and winter wheat belts and the cotton belt. The corn and soybean belts have significant increasing trends in both the annual and summertime PDSI, PHDI, and PMDI, indicating a tendency towards reduced drought conditions over time. Clear trends exist toward increasingly extreme (dry or wet) annual PDSI, PHDI, and PMDI values in the northeast, east north central, central, northwest, and west climate regions. The northeast, northwest, and west climate zones display significant temporal trends for increasingly extreme PDSI, PHDI, and PMDI values during the summertime. Trends toward increasingly variable annual and summertime drought index values are also apparent in the northeast, southwest, northwest, and west climate zones.
Comments: 16 Pages.
[v1] 2012-12-27 21:30:35
Unique-IP document downloads: 193 times
Vixra.org is a pre-print repository rather than a journal. Articles hosted may not yet have been verified by peer-review and should be treated as preliminary. In particular, anything that appears to include financial or legal advice or proposed medical treatments should be treated with due caution. Vixra.org will not be responsible for any consequences of actions that result from any form of use of any documents on this website.
Add your own feedback and questions here:
You are equally welcome to be positive or negative about any paper but please be polite. If you are being critical you must mention at least one specific error, otherwise your comment will be deleted as unhelpful.