We evaluate a decadal ozone profile record derived from the Suomi National Polar-orbiting Partnership (SNPP) Ozone Mapping and Profiler Suite (OMPS) Limb Profiler (LP) satellite instrument. In 2023, the OMPS LP data were re-processed with the new version 2.6 retrieval algorithm that combines measurements from the ultraviolet (UV) and visible (VIS) parts of the spectra and employs the second order Tikhonov regularization to retrieve a single vertical ozone profile between 12.5 km (or cloud tops) and 57.5 km with the vertical resolution of about 1.9 - 2.5 km between 20-55 km. The algorithm uses radiances measured at six UV ozone-sensitive wavelengths (295, 302, 306, 312, 317 and 322 nm) paired with 353 nm, and one VIS wavelength at 606 nm combined with 510 nm and 675 nm to form a triplet. Each wavelength pair or triplet is used over a limited range of tangent altitudes where the sensitivity to ozone changes are strongest. A new implemented aerosol correction scheme is based on a gamma-function particle size distribution. Numerous calibration changes that affected ozone retrievals were also applied to measured LP radiances, including updates in altitude registration, radiometric calibration, stray light, and spectral registration. The key version 2.6 improvement is the reduction in relative drifts between LP ozone and correlative measurements, linked previously to a drift in the version 2.5 LP altitude registration. We compare LP ozone profiles with those from Aura Microwave Limb Sensor (MLS) to quantify ozone changes in version 2.6.

A wide variety of research applications require knowledge of total solar irradiance (TSI) and solar spectral irradiance (SSI) on time scales from minutes to centuries. The current satellite data record of TSI and ultraviolet SSI is 40 years long while observations of solar irradiance at visible wavelengths through the near-infrared span 15 years. In late 2017, the NASA Total and Spectral Solar Irradiance Sensor-1 (TSIS-1) mission was deployed on the International Space Station (ISS); these new TSI and SSI datasets are now extending the observational solar irradiance record with a planned 5-year mission. Recognizing the need for ongoing specification of solar irradiance, the National Centers for Environmental Information established the Solar Irradiance Climate Data Record (CDR) in 2014. The CDR includes a composite record of TSI observations and estimates of solar total and spectral irradiance variations during, and prior, to the space-based record based on the Naval Research Laboratory (NRL) models. Utilizing as inputs proxies of sunspot darkening and facular brightening, the models specify TSI and SSI annually since 1610 and daily since 1882. Both the observational composite and the model specifications are updated regularly and will eventually utilize the new TSIS-1 observations, both to extend the observational composite and to validate and improve the models. With the goal of establishing the utility of the NRL models in specifying the time and wavelength dependence of solar variability for the Solar Irradiance CDR, we compare the latest NRLTSI2 and NRLSSI2 modeled irradiances with observations, including composite records, and with independent models of solar irradiance variability. Our assessments quantify current understanding of solar irradiance variability on multiple timescales and identify areas where TSIS-1 observations are expected to provide improved understanding of solar irradiance variability. We use the following datasets in our comparisons: TSIS-1, Solar Radiation and Climate Experiment (SORCE), Ozone Monitoring Instrument (OMI), Solar Irradiance Data Exploitation (SOLID), Spectral and Total Irradiance Reconstructions for the Satellite Era (SATIRE-S), a three-dimensional extension of the SATIRE-S model (SATIRE-3D), and Empirical Irradiance Reconstruction (EMPIRE).

The solar spectral irradiance (SSI) data set is a key record for studying and understanding the energetics and radiation balance in Earth’s environment. Understanding the long-term variations of the SSI over time scales of the 11-year solar activity cycle and longer is critical for many Sun-climate research topics. There are satellite measurements of the SSI since the 1970s that contribute to understanding the solar variability over Solar Cycles (SC) 21 to 24, with most of these SSI measurements in the ultraviolet and only recently in the visible and near infrared for SC-23 and SC-24. A limiting factor for the accuracy of the previous results is the uncertainties for the instrument degradation corrections. Analyses of the past SSI data sets have identified some irradiance offsets and some small residual instrumental trends. These corrections are applied and then combined with a previous SSI composite data set, called the GSFCSSI2 composite, to provide a new SSI composite, called the LASP GSFC SSI #3 (or SSI3). This improved composite extends the wavelength coverage down to 0.5 nm and up to 1600 nm and the time coverage up to 2020. The solar variability results from the SSI3 are consistent, of course, with the observations from which are used to create the SSI3, but they do differ with some solar variability models, in particular at longer than 900 nm. The development of the SSI3 composite also clarifies the importance of overlapping missions for studying the 11-year solar activity cycle, particularly for wavelengths longer than 200 nm.

We describe our Solar Aerosol and Gas Experiment (SAGE) III/ISS cloud detection algorithm. As in previous SAGE II/III studies this algorithm uses the extinction at 1022 nm and the extinction color ratio 520nm/1022nm to separate aerosols and clouds. We identify three types of clouds: visible cirrus (extinction coefficient > 3x10-2 km-1, subvisible cirrus (extinction < 3x10-2 km-1 and >10-3 km-1), and very low extinction cloud-aerosol mixtures (extinction < 10-3 km-1). Visible cirrus cannot be quantitatively measured by SAGE because of its high extinction, but we infer the presence of cirrus through the solar attenuation of the SAGE vertical scan. We then assume that cirrus layers extend 0.5 km below the scan termination height. SAGE cirrus cloud fraction estimated this way is in qualitative agreement with CALIPSOmeasurements. Analyzing three years of SAGE III/ISS data, we find that visible cirrus and subvisible cirrus have nearly equal abundance in the tropical upper troposphere and the average cloud fraction is about 25%. At 16 km, the highest concentration visible cirrus and subvisible cirrus is over the Tropical West Pacific, central Africa and central South America during winter. Latitudinal gaps in zonal mean cloud fraction and average aerosol extinction apparent in the subtropical transition region are aligned with descending branch of the residual mean circulation. We also identify four anomalous aerosol extinction periods that can be tentatively assigned to significant volcanic or fire events. Using tropopause relative coordinates, we show that maximum cloud top heights are consistently restricted to a narrow region near the tropopause.

Seasonal ozone depletion in the polar regions (during late winter and early spring) depends on the presence and distribution of polar stratospheric clouds (PSCs). In this paper, we present new satellite observations of PSCs by the Ozone Mapping and Profiler Suite (OMPS) Limb Profiler (LP) instrument. LP cloud detections are identified as PSCs based on location, altitude, and background atmosphere temperature. The hyperspectral capabilities of OMPS LP enable PSC detection to occur concurrent with stratospheric ozone measurements from the same instrument. We present PSC results from the Northern Hemisphere 2019-2010 winter/spring season to illustrate the exceptional nature of this season. Future OMPS LP instruments flying on Joint Polar Satellite System (JPSS) satellites will continue PSC observations into the 2030s.

Key Points • NRLSSI2h solar irradiance variability model with 0.1-0.5 nm resolution captures larger UV. spectral line variability relative to continua. • At 300-400 nm, dominated by spectral features, NRLSSI2h estimates 2-5X smaller solar cycle variability than radiative transfer models. • Upper atmosphere solar radiation absorption can differ using NRLSSI2h (e.g., 34% decrease at 88 km for Lyman alpha).