Comparison of ionospheric F2-layer peak height (hmF2) derived by ionosonde with IRI-2016 model at Chumphon, Thailand

In this paper, the ionospheric F2-layer peak height (hmF2) is investigated and compared with the International Reference Ionosphere 2016 (IRI-2016) model over Thailand equatorial latitude station, namely Chumphon (10.72°N, 99.37°E, dip angle 3.0°N). The hmF2 values are derived from M(3000)F2 values that are manually scaled from the ionograms recorded by the ionosonde measurement. The hmF2 values predicted by IRI-2016 model are 3 options as (1) BSE-1979, (2) AMTB-2013, and (3) SHU-2015. The monthly hourly median of hmF2 values in March, June, September, and December of the year 2009 are analyzed the hourly, daily and monthly variations during low solar activity. The results show similar trends between observed and modeled in that they increase from sunrise to noontime hours and decrease from afternoon to pre-sunrise hours. Three options of the IRI-2016 model predicts hmF2 values underestimate for daytime and overestimate for nighttime. The BSE-1979 option shows the best agreement while the AMTB-2013 option shows the worst over Chumphon equatorial latitude station. The hmF2 percentage deviation (%PD) changes from -20% to 10% at daytime and varies among 0% and 30% for nighttime. These comparative results are used to improve the IRI model in the future.