10.18170/DVN/I9JJIYDonghe Zhang0000-0002-3880-2426Peking UniversityPeking University Open Research Data Platform2021Earth and Environmental SciencesYongqiang HaoPeking University2021-09-012021-09-01736633330text/plaintext/plaintext/plain1.0CC0 WaiverHere two files include the ionospheric foF2 and hmF2 data observed at China Haikou ionosonde station (20.02°N, 110.2°E, MLAT~ 9.32°N) in 2003 (16 April to 31 May) and in 2004 (21 Sep to 26 Oct ), respectively. The first column is the Day of year (DOY), the second column is the foF2(Mhz), the third column is the hmF2(km).