Ice Radiative Effects Research Articles

Investigating the “Too Bright” Issue Pertaining to Non‐PBL Clouds Over the South Pacific Trade‐Wind Region in CMIP6 Global Climate Models

AbstractThis paper examines the “too bright” issue pertaining to non‐planetary boundary layer (PBL) clouds over the South Pacific trade‐wind region and its potential link to the falling ice radiative effects (FIREs). We run sensitivity experiments with CESM2‐CAM6 (CESM2) global climate model with FIREs on (SON) and off (NOS). The model exhibits more in‐cloud liquid water content (CLWC) and droplet above the PBL in NOS, leading to larger shortwave (SW) reflectivity at the top of the atmosphere than in SON over the trade wind regions. CMIP6 models are divided into three subsets: separately calculates the radiative effects of cloud ice and falling ice (SON2), combined (SON1) and without falling ice (NOS). SON2 models exhibit improved CLWC and SW reflectivity similar to CESM2‐SON, while NOS and SON1 models are akin to CESM2‐NOS owing to weaker surface wind stress and warmer ocean surface, caused by the lack of FIREs over the convective zones.

Assessing the Impacts of Falling Ice Radiative Effects on the Seasonal Variation of Land Surface Properties

AbstractThe impacts of falling ice radiative effects (FIREs) on land‐atmosphere feedback processes were examined, with a focus on the fidelity of land surface properties and their variability as inferred by global climate models (GCMs). We conducted a pair of sensitivity experiments using the National Center for Atmospheric Research (NCAR) Community Earth System Model Version 1 (CESM1) in fully coupled modes with FIREs turned on and off. This allowed us to investigate the seasonal response of land surface properties to changes in radiation fluxes and land surface temperature (LST) associated with FIREs across global land areas. Our findings indicate that during boreal winter, excluding FIREs results in less surface downward longwave and net flux (∼5–15 Wm−2), leading to a colder land surface (∼2–4 K) and air temperatures (∼1–4 K) at mid‐ and high latitudes. Consequently, the surface frozen soil layer and snow cover persist through spring, delaying snowmelt and thawing until summer. This delay reduces liquid soil moisture, thereby suppressing vegetation productivity in subsequent seasons. Conversely, tropical regions, exhibit contrasting responses, with a warmer land surface (∼0.5 K) and warmer air temperatures (∼0.1–0.5 K) due to increased surface downward shortwave and net flux (∼2–10 Wm−2). This enhancement in radiation fosters increased vegetation productivity throughout the seasonal cycle. These findings illustrate a local response of land surface properties to changes in the surface energy balance and LST, highlighting the significant role that FIREs play in land surface modeling within GCMs.

Evaluation of Radiatively Active Frozen Hydrometeors Mass in CMIP6 Global Climate Models Using CloudSat‐CALIPSO Observations

AbstractThis study uses derived 2C‐ICE estimates of frozen hydrometeors path (IWP) and vertical profile of ice water content (IWC) from CloudSat‐CALIPSO satellite measurements to evaluate stratiform floating ice (CIWP/CIWC), falling ice (snow) (SWP/SWC) and total ice (TIWP/TIWC) simulated by three subsets of CMIP6 models. They include those neglecting the falling ice (snow) radiative effects (NOS) or those considering these effects (SON) but with separate (SON2) or combined (SON1) frozen hydrometeors (cloud ice and falling ice) interacting with radiation. CIWP from NOS subset agrees with 2C‐ICE estimates better than SON2 except for overestimating over the trade‐wind regions. This is also the case for vertical profiles of regionally‐averaged CIWC, with the exception of overestimates in the lower troposphere of high latitudes by NOS. Falling ice (SWP/SWC) is simulated reasonably well in SON2 models against 2C‐ICE estimates, but with significant underestimates over mid‐ and high‐latitudes. Vertical shapes of regionally‐averaged SWC profiles are well reproduced but magnitudes are underestimated for all regions except for the middle troposphere of the tropical region. The inclusion of snow improves the agreement between the simulated TIWP/TIWC of SON1 and SON2 subsets and 2C‐ICE estimates, compared to the NOS subset. However, TIWP/TIWC are underestimated over the storm track and high latitude for all three subsets except for the tropical region of SON2. The aforementioned discrepancies are likely due to model physics, but observational estimates of frozen hydrometeors mass and content are also highly uncertain. Further studies are needed to improve both models and observational estimates of frozen hydrometeors mass.

Warm Clouds Biases in CMIP6 Models Linked to Indirect Effects of Falling Ice‐Radiation Interactions Over the Tropical and Subtropical Pacific

AbstractWe examine the spatial distributions of CMIP6‐simulated cloud liquid water path (CLWP) and content (CLWC) against MODIS and CloudSat synthesized data over the tropical and subtropical Pacific. Three subsets of models are categorized based on their treatments of frozen ice‐radiative interactions. CLWP/CLWC are generally well simulated in subset with separately‐calculated radiative effects of cloud ice and falling ice (SON2). Too much warm clouds above 750 hPa are produced in either subset with total frozen ice radiative effects (SON1) or subset without radiative effects of falling ice (NOS) and thus CLWP/CLWC are overestimated over the open ocean including the trade‐wind regions. Stratocumulus clouds off the coasts of North and South America are severely underestimated in NOS models. We attribute the overestimates of clouds above the trade‐wind boundary layers to anomalous ascending motion associated with warmer sea surface temperature and weaker surface wind stress linked to indirect effects of falling ice‐radiation interactions.

Possible linkage of sea surface height anomaly, surface wind stress and sea surface temperature with the falling ice radiative effects under a gradual warming scenario

This study investigates the possible linkage of sea surface height anomaly (SSHA), sea surface temperature (SST) and surface wind stress (TAU) with the falling ice radiative effects (FIREs) over the Pacific Ocean under the CMIP5 scenario of 1% CO2 increase per year (1pctCO2) for 140 years. Two sensitivity experiments using the fully-coupled ocean-atmosphere CESM1-CAM5 model are compared: one with FIREs (SON) and the other without (NOS). The warming period of the last 20 year is compared to the control period of the first 20 years. The mean state of the first 20 years exhibits a stronger west-east SSHA gradient in SON than in NOS over the Pacific Ocean, attributed to the stronger prevailing easterly trade winds and the SST pattern of being warmer in the western Pacific but colder in the eastern Pacific. In the last 20 years, SON continues to display a stronger SSHA west-east gradient with higher sea level and SST over the western Pacific Ocean compared to NOS. In the southwest Pacific, stronger trade winds are linked with the wind-evaporation-SST feedback, leading to a more significant decline in SSHA there in SON than in NOS. The CMIP5 ensemble mean shows similar relationships of SSHA with TAU and SST to those of NOS when both are compared against SON, highlighting the importance of FIREs in the SSH projection over the Pacific Ocean and the impact of FIREs on the changing relationships between SSHA, SST and TAU under global warming.

Inferring the linkage of sea surface height anomalies, surface wind stress and sea surface temperature with the falling ice radiative effects using satellite data and global climate models

This study attempts to infer the linkage of sea surface height anomaly (SSHA), surface wind stress and sea surface temperature with the falling ice (snow) radiative effects (FIREs) over the tropical and subtropical Pacific Ocean using CESM1-CAM5 sensitivity experiments with FIREs-off (NOS) and on (SON) under CMIP5 historical run. The obs4MIPs monthly SSH data based upon satellite measurements are used as a reference. The seasonal and annual mean spatial patterns of SSHA difference between NOS and SON are tightly linked to those of SST and TAU over the study domain, in particular, over the south Pacific. Compared with NOS, SON simulates improved seasonal and annual mean SSHA associated with improved sea surface temperature (SST), surface wind stress (TAU) over the trade-wind areas. In SON, the simulated mean absolute bias of SSHA over the study domain is reduced (up to 30%) against NOS relative to observations. The SSHA biases are then compared with CMIP5 models. Despite the biases of SST and SSHA over the south and north flanks of the equator in SON, the seasonal variations of improved SSHA are closely related to those of TAU and SST resulting from the FIREs; that is, higher SSHA is associated with weaker TAU and warmer SST changes and vice versa. The CMIP5 ensemble mean absolute biases of SSHA show similarities to NOS mainly over the south Pacific.

Comparing surface wind stress and sea surface temperature biases over the tropical and subtropical oceans in subsets of CMIP6 models categorized by frozen hydrometeors-radiation interactions

We evaluate the simulations of surface wind stress (TAU) and sea surface temperature (SST) over subtropical and tropical Pacific and Atlantic oceans in subsets of CMIP6 models that are categorized by frozen hydrometeors-radiation interactions. The CMIP6 models are divided into two subsets with combined (SON1) and separated (SON2) radiative properties of cloud ice and falling ice (snow) and compared to the set with cloud ice radiative effects only (NOS). There is evidence that these hydrometeors-radiation interaction treatments induce different atmospheric dynamic responses that influence the surface properties. Excessive westerly TAU and meridional TAU divergence away from convective zones are reduced significantly in SON1 and SON2 relative to NOS against QuikSCAT observations; while the differences between SON2 and SON1 are small. SON2 reduces cold SST biases over north oceans and equatorial zones drastically (1 to 2 K), and warm biases (up to 1 K) off the coasts of America and zonal TAU biases are reduced relative to NOS. Unlike SON2, SON1 improves SSTs mainly over south of Pacific Ocean and limited areas over the tropical belts relative to NOS although TAU is reduced drastically as in SON2, implying that other factors play a role in degrading the SST simulations in SON1 relative to SON2. SON2 outperforms NOS and SON1 in the seasonal cycles of SST mean biases and mean absolute biases averaged over the equatorial area, north ocean, and South Pacific against ERSST observations. Despite the significant improvements in TAU and SST simulations, SON2 models still exhibit non-trivial biases over south and north flanks of equatorial zones. These results suggest that there are direct linkages of TAU with SST changes resulting from the hydrometeors-radiation interactions in SON2, but not in SON1, relative to NOS, implying that a separated treatment of cloud ice and falling ice radiative properties in climate models is preferred.

Exploring Radiation Biases Over the Tropical and Subtropical Oceans Based on Treatments of Frozen‐Hydrometeor Radiative Properties in CMIP6 Models

AbstractTo explore the impacts of hydrometeor radiative effects over subtropical and tropical Pacific and Atlantic Oceans, we quantify the mean radiation biases in historical climate simulations based on how frozen‐hydrometeors radiative properties are calculated in CMIP6 models. CMIP6 models are divided with cloud ice only (NOS), with combined (SON1), and with separate treatments (SON2) of cloud ice and falling ice (snow) radiative properties. Over the deep convective regions, NOS models overestimate outgoing longwave radiation (RLUT) and surface shortwave irradiance (RSDS), while underestimate top‐of‐atmosphere reflected shortwave radiation (RSUT). SON2 models reduce these biases by 4–14 W m−2. However, this improvement is not seen in SON1 against NOS. Spatially averaged absolute biases in radiative fluxes for SON1 models are larger than those of NOS, suggesting that the SON1 approach of falling ice radiative effects may not produce the expected hydrometeor–radiation interactions. Over the south Pacific trade‐wind regions, both SON2 and SON1 show similar improvements in RLUT, RSUT, and RSDS with positive absolute bias differences up to 20 W m−2 against NOS, leading to improvement of CMIP6 over CMIP5 ensembles. The seasonal cycles are consistent with the annual means over these two regions except with larger differences between subsets of models during January–May than during June–December. In general, improvement from CMIP5 to CMIP6 due to more participating SON2 models is limited because of offset by SON1. These results suggest that a separate treatment of frozen‐hydrometeor radiative properties may be critical for reducing the spread of CMIP models.

Observational evaluation of global climate model simulations of arctic sea ice and adjacent land pertaining to the radiative effects of frozen hydrometeors

This study explores the linkage of frozen hydrometeors (cloud ice and falling ice/snow) with sea ice and adjacent lands through surface energy budget using model-observation comparisons to quantify the roles of the falling ice radiative effects (FIREs) in determining the extent and thickness of Arctic sea ice and adjacent land surface radiation budget and land surface skin (Ts) and surface (SAT) temperatures. The Coupled Model Intercomparison Project Phase 5 (CMIP5) models without FIREs tend to produce underestimated downward longwave radiation, and overestimated shortwave downward radiation and surface albedo, resulting in too-cold skin temperature (TS) and surface air temperature (SAT) and overestimated sea ice concentration (SIC) and thickness (SIT). By comparing two simulations of late 20th Century climate from CESM1-CAM5 model with inclusion and exclusion of FIREs, it is found that TS, SAT, radiation, SIC, and SIT and their seasonal cycles are improved with the inclusion of FIREs. Exclusion of FIREs results in underestimated net downward longwave radiative flux, which is highly correlated with overestimated surface albedo, colder TS, and SAT with a confidence level at 99% (p < 1%). These biases in CESM1-CAM5 resemble those in CMIP5 models without FIREs. With the inclusion of FIREs, the SIC bias is reduced by 2%–15% in summer, while the SIT is improved up to 90% in winter despite little improvement in SIC. These findings suggest a potential link among the increased downward longwave flux, decreased downward shortwave flux, and decreased surface air and land surface temperatures locally, which then drives SIC melting and SIT thinning when FIREs are included relative to when FIREs are excluded. It is suggested that the roles played by FIREs over the Arctic regions are of the same order of importance as those over the Southern Oceans despite the differences in geography and impact of human activity.

The potential influence of falling ice radiative effects on Central-Pacific El Niño variability under progressive global warming

The impacts of falling ice (snow) radiative effects (FIREs) on simulated surface wind stress and sea surface temperature (SST) in Central Pacific El Niño (CP-El Niño) under a progressive warming climate are examined. Using controlled simulations with the CESM1 model, it is shown that the exclusion of FIREs (no snow: NOS) generates persistent westerly anomalies in surface wind stress relative to that with FIREs (snow on: SON). These anomalies subsequently lead to a weakening of the easterly trade winds associated with warmer SST anomalies in modeled life cycle. Results over three separated 40 year intervals (P1: 21–60 years; P2: 61–100 years; P3: 101–140 years) are compared with Coupled Model Intercomparison Project phase 5 (CMIP5) models without FIREs. Both NOS configuration and CMIP5 models simulate longer life cycles of CP-El Niño events with weakening easterlies and warmer SST anomalies on the equator, persistently propagating eastward from the mature to dissipating phases. Compared to NOS, SON, on the other hand, produces a shorter CP-El Niño life cycle together with stronger easterlies and colder SSTs over the eastern to central equatorial Pacific. The magnitudes of the simulated westerlies and warm SST anomalies tend to diminish without eastward shifting following the peak of the CP-El Niño activity. There are substantial differences in CP-El Niño characteristics from P1 to P3 between NOS and SON. During P1, both SON and NOS show patterns which are consistent with their present-day counterparts. In P2 and P3, SON exhibits a prolonged CP-El Niño life cycle, while NOS develops a double-peak El Niño evolution at the mature and decaying phases. Regarding El Niño diversity and the projections, the CMIP5 models have not reached a consensus. The inclusion of the FIREs would increase the confidence in simulating El Niño future behavior.

Changes of South‐Central Pacific Large‐Scale Environment Associated With Hydrometeors‐Radiation‐Circulation Interactions in a Coupled GCM

AbstractA common deficiency in coupled atmosphere‐ocean models is the lack of stratocumulus clouds near the west coasts of continents and shallow cumulus clouds over the trade wind regions. In this study, we examine changes of large‐scale trade wind environment associated with hydrometeors‐radiation‐circulation interactions, focusing over the south‐central Pacific, by carrying out experiments with falling ice (snow) radiative effects (FIREs) on or off using the CESM1‐CAM5 coupled model. Compared to observations/reanalysis data and an experiment with FIREs on (SON), an experiment with FIREs off (NOS) tends to have too‐high (0.3–0.9 K) sea surface temperature (SST) over the eastern half of the Pacific, and weaker surface wind stress over the northeast side but stronger stress over the southwest side of the study domain. The difference between NOS and SON shows lower‐tropospheric wind fields with a cyclonic‐like wind pattern, which is similar to surface wind stress, accompanied with weaker subsidence over the northeast side. The cyclonic‐like wind pattern causes stronger moisture convergence, accompanied with horizontal warm and moist advections, and stronger effective ascending motion over the northeast side of the study domain, building large‐scale environmental conditions to facilitate middle‐ and high‐clouds instead of shallow cumulus clouds in nature. This large‐scale environment in conjunction with the higher SSTs may be also responsible for the lack of the stratocumulus clouds near the coast of America. Remaining biases in SON such as the double intertropical convergence zone and parameterization deficiencies may also prevent a more realistic simulation of trade wind clouds and their associated large‐scale environments.

Impacts of falling ice radiative effects on projections of Southern Ocean sea ice change under global warming

Impacts of falling ice radiative effects on projections of Southern Ocean sea ice change under global warming

Annual and seasonal mean tropical and subtropical precipitation bias in CMIP5 and CMIP6 models

Annual and seasonal mean tropical and subtropical precipitation biases in present-day climate simulations by phase 6 of the Coupled Model Intercomparison Project (CMIP6) models are evaluated. We analyze 23 CMIP6 models, which are grouped into those without (NOS) and with (SON) falling ice (snow) radiative effects (FIREs). The SON group is further divided according to treatments of ice-cloud radiative properties with separate (SON2) and combined cloud ice and snow contents (SON1). SON2 mitigates precipitation bias drastically relative to NOS, but SON1 overestimates precipitation in the subtropics, which deteriorates its performance relative to SON2 and NOS. Large offsets between SON2 and SON1 and between SON and NOS contribute to the slight improvement of CMIP6 relative to CMIP5, largely due to the contribution of SON2. The different treatments of ice-cloud radiative properties between SON2 and SON1 seem to be potentially linked to differences in precipitation biases. Results suggest that further in-depth investigation of cloud ice–radiation–circulation interactions is required.

An Overview of CMIP5 and CMIP6 Simulated Cloud Ice, Radiation Fields, Surface Wind Stress, Sea Surface Temperatures, and Precipitation Over Tropical and Subtropical Oceans

AbstractThe potential links between ice water path (IWP), radiation, circulation, sea surface temperature (SST), and precipitation over the Pacific and Atlantic Oceans resulting from the falling ice radiative effects (FIREs) are examined from Coupled Model Intercomparison Project phase 5 (CMIP5) and phase 6 (CMIP6) historical simulations. The latter is divided into two subsets with (SON6) and without FIREs (NOS6) in CMIP6. Improvement in nonfalling cloud ice (~20 g m−2) is noticeable over convective regions in CMIP6 relative to CMIP5. The inclusion of FIREs in SON6 subset may contribute to reduce biases of overestimated outgoing longwave radiation and downward surface shortwave and underestimated reflected shortwave at the top of the atmosphere (TOA) by magnitudes of ~8 W m−2 over convective regions against CERES, compared to NOS6 subset. The reduced biases in radiative fluxes in convective regions stabilize the atmosphere and lead to circulation, SST, cloud, and precipitation changes over the trade wind regions, as seen from improved radiative fluxes (~15 W m−2), surface wind stress biases, SST (~0.8 K), and precipitation (1 mm day−1) biases. The significant improvement from NOS6 to SON6 leads to improved multimodel means for CMIP6 relative to CMIP5 for radiation fields over the trade wind regions but the degradation over convective zones is attributed to NOS6 subset. The results suggest that other sources of uncertainty and deficiencies in climate models may play significant roles for reducing discrepancies although FIREs, via radiation‐circulation coupling, may be one of the factors that help to reduce regional biases.

Evaluation of sea salt aerosols in climate systems: global climate modeling and observation-based analyses**The data that support the findings of this study are available from the corresponding author upon reasonable request.

Sea salt aerosols (SSA), one of the most abundant aerosol species over the global oceans, play important roles for Earth’s climate. State-of-the-art SSA parameterizations in global climate models (GCMs) are typically modeled using near-surface wind speed, sea surface temperature (SST), and precipitation. However, these have non-trivial biases in CMIP3 and CMIP5 GCMs over the tropical Pacific Ocean that can contribute to biases in the simulated SSA. This study investigates the impacts of falling ice radiative effects on the biases of the aforementioned modeled parameters and the resulting modeled SSA biases. We compare the CMIP5 modeled SSA against satellite observations from MISR and MODIS using a pair of sensitivity experiments with falling ice radiative effects on and off in the CESM1-CAM5 model. The results show that when falling ice radiative effects are not taken into account, models have weaker surface wind speeds, warmer SSTs, excessive precipitation, and diluted sea surface salinity (SSS) over the Pacific trade-wind regions, leading to underestimated SSA. In the tropical Pacific Ocean, the inclusion of falling ice radiative effects leads to improvements in the modeled near-surface wind speeds, SSTs, and precipitation through cloud-precipitation-radiation-circulation coupling, which results in more representative patterns of SSA and reduces the SSA biases by ∼10% to 15% relative to the satellite observations. Models including falling ice radiative effects in CMIP5 produce smaller biases in SSA than those without falling ice radiative effects. We suggest that one of the causes of these biases is likely the failure to account for falling ice radiative effects, and these biases in turn affect the direct and indirect effects of SSA in the GCMs.

The role of falling ice radiative effects on climate projections over Arctic under global warming

The role of falling ice radiative effects on climate projections over Arctic under global warming

Relating Precipitating Ice Radiative Effects to Surface Energy Balance and Temperature Biases Over the Tibetan Plateau in Winter

Key Points Surface temperature bias is primarily determined by biases of surface radiative fluxes Underestimated ice water path in models is related to radiation deficiency and cold bias over the Tibetan Plateau in winter Precipitating ice radiative effects are responsible for some reduction of biases in surface radiative fluxes and temperature

Potential faster Arctic sea ice retreat triggered by snowflakes' greenhouse effect

Abstract. Recent Arctic sea ice retreat has been quicker than in most general circulation model (GCM) simulations. Internal variability may have amplified the observed retreat in recent years, but reliable attribution and projection requires accurate representation of relevant physics. Most current GCMs do not fully represent falling ice radiative effects (FIREs), and here we show that the small set of Coupled Model Intercomparison Project Phase 5 (CMIP5) models that include FIREs tend to show faster observed retreat. We investigate this using controlled simulations with the CESM1-CAM5 model. Under 1pctCO2 simulations, including FIREs results in the first occurrence of an “ice-free” Arctic (monthly mean extent &lt;1×106 km2) at 550 ppm CO2, compared with 680 ppm otherwise. Over 60–90∘ N oceans, snowflakes reduce downward surface shortwave radiation and increase downward surface longwave radiation, improving agreement with the satellite-based CERES EBAF-Surface dataset. We propose that snowflakes' equivalent greenhouse effect reduces the mean sea ice thickness, resulting in a thinner pack whose retreat is more easily triggered by global warming. This is supported by the CESM1-CAM5 surface fluxes and a reduced initial thickness in perennial sea ice regions by approximately 0.3 m when FIREs are included. This explanation does not apply across the CMIP5 ensemble in which inter-model variation in the simulation of other processes likely dominates. Regardless, we show that FIRE can substantially change Arctic sea ice projections and propose that better including falling ice radiative effects in models is a high priority.

Falling Snow Radiative Effects Enhance the Global Warming Response of the Tropical Pacific Atmosphere

AbstractMost models from the Coupled Model Intercomparison Project phase 5 (CMIP5) do not include the radiative effects of falling snow. This has been shown to bias simulations of radiation and circulation in the Pacific present‐day mean state. Here we explore how precipitating ice radiative effects contribute to simulated Pacific climate change via a pair of sensitivity experiments with and without snow radiative effects (SnowOn/SnowOff) using 1pctCO2 simulations of the Community Earth System Model version 1 (CESM1) climate model, in which atmospheric CO2 increases at 1% per year for 140 years. In addition, we compare our results with the CMIP5 ensemble mean. The initial climate state of each 1pctCO2 run shows similar patterns to present‐day simulations. Under global warming, the regions of convective activity tend to intensify and shift eastward. These changes are stronger in the SnowOn simulation, which also displays a stronger zonal gradient of sea surface temperature warming relative to SnowOff. The changes in convective activity and the associated precipitation are particularly notable: with reduced precipitation around the maritime continent, and an approximate doubling of the precipitation increase over parts of the western Pacific in SnowOn. CESM1 SnowOff patterns of change are similar to those in CMIP5 models that exclude snow radiative effects, hinting that future warming‐driven changes in precipitation and circulation over the Pacific might be stronger than those simulated by most CMIP5 models.

The Impacts of Bias in Cloud‐Radiation‐Dynamics Interactions on Central Pacific Seasonal and El Niño Simulations in Contemporary GCMs

AbstractMost of the global climate models (GCMs) in the Coupled Model Intercomparison Project, phase 5 do not include precipitating ice (aka falling snow) in their radiation calculations. We examine the importance of the radiative effects of precipitating ice on simulated surface wind stress and sea surface temperatures (SSTs) in terms of seasonal variation and in the evolution of central Pacific El Niño (CP‐El Niño) events. Using controlled simulations with the CESM1 model, we show that the exclusion of precipitating ice radiative effects generates a persistent excessive upper‐level radiative cooling and an increasingly unstable atmosphere over convective regions such as the western Pacific and tropical convergence zones. The invigorated convection leads to persistent anomalous low‐level outflows which weaken the easterly trade winds, reducing upper‐ocean mixing and leading to a positive SST bias in the model mean state. In CP‐El Niño events, this means that outflow from the modeled convection in the central Pacific reduces winds to the east, allowing unrealistic eastward propagation of warm SST anomalies following the peak in CP‐El Niño activity. Including the radiative effects of precipitating ice reduces these model biases and improves the simulated life cycle of the CP‐El Niño. Improved simulations of present‐day tropical seasonal variations and CP‐El Niño events would increase the confidence in simulating their future behavior.