干旱 

Pinyin: gānhàn 
Meaning：Drought 
Sentence：干旱地区需要灌溉才能使作物生长。Irrigation is needed to make crops grow in dry regions.

More: 

干： 

Pinyin: gàn, gān
Meaning: Shield; dry
Radical: 干
Stokes: 3
Traditional: 乾
Common words/Phrase:
干扰[gānrǎo] 【obstruction; interfere】
干净[gānjìng] 【clean; neat】
干燥[gānzào] 【dry; arid; dull】
干涉[gānshè] 【interfere】

旱： 

Pinyin: hàn
Meaning: Drought
Radical: 日
Stokes: 7
Traditional: 旱
Common words/Phrase:
旱灾[hànzāi] 【drought】 
旱情[hà qíng] 【ravages of a drought】
旱田[hàntián] 【glebe】
旱烟[hànyān] 【tobacco】
旱作[hànzuò] 【dry farming】