Abstract. The amount of ice injected into the tropical tropopause layer has a strong radiative impact on climate. A companion paper (Part 1) used the amplitude of the diurnal cycle of ice water content (IWC) as an estimate of ice injection by deep convection, showed that the Maritime Continent (MariCont) region provides the largest injection to the upper troposphere (UT; 146 hPa) and to the tropopause level (TL; 100 hPa). This study focuses on the MariCont region and extends that approach to assess the processes, the areas and the diurnal amount and duration of ice injected over islands and over seas during the austral convective season. The model presented in the companion paper is again used to estimate the amount of ice injected (ΔIWC) by combining ice water content (IWC) measured twice a day by the Microwave Limb Sounder (MLS; Version 4.2) from 2004 to 2017 and precipitation (Prec) measurements from the Tropical Rainfall Measurement Mission (TRMM; Version 007) binned at high temporal resolution (1 h). The horizontal distribution of ΔIWC estimated from Prec (ΔIWCPrec) is presented at 2∘×2∘ horizontal resolution over the MariCont. ΔIWC is also evaluated by using the number of lightning events (Flash) from the TRMM-LIS instrument (Lightning Imaging Sensor, from 2004 to 2015 at 1 h and 0.25∘ × 0.25∘ resolution). ΔIWCPrec and ΔIWC estimated from Flash (ΔIWCFlash) are compared to ΔIWC estimated from the ERA5 reanalyses (ΔIWCERA5) with the vertical resolution degraded to that of MLS observations (ΔIWCERA5). Our study shows that the diurnal cycles of Prec and Flash are consistent with each other in phase over land but different over offshore and coastal areas of the MariCont. The observational ΔIWC range between ΔIWCPrec and ΔIWCFlash, interpreted as the uncertainty of our model in estimating the amount of ice injected, is smaller over land (where ΔIWCPrec and ΔIWCFlash agree to within 22 %) than over ocean (where differences are up to 71 %) in the UT and TL. The impact of the MLS vertical resolution on the estimation of ΔIWC is greater in the TL (difference between ΔIWCERA5 and 〈ΔIWCERA5〉 of 32 % to 139 %, depending on the study zone) than in the UT (difference of 9 % to 33 %). Considering all the methods, in the UT, estimates of ΔIWC span 4.2 to 10.0 mg m−3 over land and 0.4 to 4.4 mg m−3 over sea, and in the TL estimates of ΔIWC span 0.5 to 3.9 mg m−3 over land and 0.1 to 0.7 mg m−3 over sea. Finally, based on IWC from MLS and ERA5, Prec and Flash, this study highlights that (1) at both levels, ΔIWC estimated over land can be more than twice that estimated over sea and (2) small islands with high topography present the largest ΔIWC (e.g., island of Java).

<p><strong>Abstract.</strong> The amount of ice injected up to the tropical tropopause layer has a strong radiative impact on climate. In the tropics, the Maritime Continent (MariCont) region presents the largest injection of ice by deep convection into the upper troposphere (UT) and tropopause level (TL) (from results presented in the companion paper Part 1). This study focuses on the MariCont region and aims to assess the processes, the areas and the diurnal amount and duration of ice injected by deep convection over islands and over seas using a 2° × 2° horizontal resolution during the austral convective season of December, January and February. The model presented in the companion paper is used to estimate the amount of ice injected (∆IWC) up to the TL by combining ice water content (IWC) measured twice a day in tropical UT and TL by the Microwave Limb Sounder (MLS; Version 4.2), from 2004 to 2017, and precipitation (Prec) measurement from the Tropical Rainfall Measurement Mission (TRMM; Version 007) at high temporal resolution (1 hour). The horizontal distribution of ∆IWC estimated from Prec (∆IWC<sup>Prec</sup>) is presented at 2° × 2° horizontal resolution over the MariCont. ∆IWC is also evaluated by using the number of lightnings (Flash) from the TRMM-LIS instrument (Lightning Imaging Sensor, from 2004 to 2015 at 1-h and 0.25° × 0.25° resolutions). ∆IWC<sup>Prec</sup> and ∆IWC estimated from Flash (∆IWC<sup>Flash</sup>) are compared to ∆IWC estimated from the ERA5 reanalyses (∆IWC<sup>ERA5</sup>) degrading the vertical resolution to that of MLS observations (<∆IWC<sup>ERA5</sup>>). Our study shows that, while the diurnal cycles of Prec and Flash are consistent to each other in timing and phase over lands and different over offshore and coastal areas of the MariCont, the observational ∆IWC range between ∆IWC<sup>Prec</sup> and ∆IWC<sup>Flash</sup> is small (to within 4–20 % over land and to within 6–50 % over ocean) in the UT and TL. The reanalysis ∆IWC range between ∆IWC<sup>ERA5</sup> and <∆IWC<sup>ERA5</sup>> has been also found to be small in the UT (22–32 %) but large in the TL (68–71 %), highlighting the stronger impact of the vertical resolution on the TL than in the UT. Combining observational and reanalysis ∆IWC ranges, the total ∆IWC range is estimated in the UT between 4.17 and 9.97 mg m<sup>−3</sup> (20 % of variability per study zone) over land and between 0.35 and 4.37 mg m<sup>−3</sup> (30 % of variability per study zone) over sea, and, in the TL, between 0.63 and 3.65 mg m<sup>−3</sup> (70 % of variability per study zone) over land and between 0.04 and 0.74 mg m<sup>−3</sup> (80 % of variability per study zone) over sea. Finally, from IWC<sup>ERA5</sup>, Prec and Flash, this study highlights (1) ∆IWC over land has been found larger than ∆IWC over sea, and (2) the Java Island is the area of the largest ∆IWC in the UT (7.89–8.72 mg m<sup>−3</sup> daily mean).</p>