Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantification of historical drought conditions over different climatic
  zones of Nigeria   The impact of extreme climate such as drought and flooding on agriculture,
tourism, migration and peace in Nigeria is immense. There is the need to study
the trend and statistics for better planning, preparation and adaptation. In
this study, the statistical and temporal variation of climatic indices
Standardized Precipitation Index (SPI ) and Standardized Precipitation
Evapotranspiration Index (SPEI) were computed for eighteen (18) stations
covering four climatic zones (Sahel, Midland, Guinea Savannah and Coastal) of
tropical Nigeria. Precipitation, minimum and maximum temperature from 1980 -
2010 obtained from the archives of the Nigerian Meteorological Services were
used to compute both the SPI and SPEI indices at 1-, 3- 6- and 12-month
timescales. The temporal variation of drought indices showed that droughts were
more prominent at 6- and 12-months timescales. SPI and SPEI were found to be
better correlated at longer timescales than short time scales. Predominant
small, positive and significant trend across the region suggest an increasing
trend due to climate change.

15
The categories of this paper are: nucl-ex
31
The categories of this paper are: ao-sci
2
The categories of this paper are: math
14
The categories of this paper are: math-ph
6
The categories of this paper are: astro-ph
0
The categories of this paper are: hep-ph
8
The categories of this paper are: hep-ex
16
The categories of this paper are: stat
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
23
The categories of this paper are: solv-int
27
The categories of this paper are: comp-gas
32
The categories of this paper are: atom-ph
4
The categories of this paper are: cond-mat
30
The categories of this paper are: q-alg
26
The categories of this paper are: bayes-an