Earth's Radiation Budget

The University of Wisconsin-Madison Space Science and Engineering Center will provide forecast support for flight planning during the 2023 SABRE Mission using global chemical and aerosol forecasts combined with ensemble trajectory based diagnostics of the histories on flight altitudes covering the range WB-57. The team will contribute to the post mission analysis by using global chemical and aerosol analyses combined with ensemble trajectory based diagnostics to characterize the histories of air parcels sampled by the WB-57. These forecast and analysis products will help to interpret the WB-57 measurements by providing estimates of the large-scale distribution of trace gases, aerosol composition, and origin (i.e. stratosphere, free troposphere, continental boundary layer, marine boundary layer) of the atmosphere sampled during SABRE.

The Unmanned aerial system (UAS) Chromatograph for Atmospheric Trace Species (UCATS) instrument suite has been deployed on numerous prior aircraft campaigns to make high quality, high resolution, in situ measurements of ozone, water vapor, N₂O, SF₆, CFC-11, CFC-12, and Halon-1211. This project replaces the main computer and flash storage in the UCATS instrument with a modern computer that is capable of running a modern operating system (LINUX) and one compatible with a solid-state drive. The project also involves writing new software to drive and communicate with various devices (gas sample valves, temperature controllers, etc.) and to store and process data obtained during operation.

The determination of atmospheric composition trends in the upper troposphere/lower stratosphere (UTLS) is still highly uncertain due to large atmospheric variability driven by chemistry, mixing, and dynamics (reflected in the tropopause and jet variations). Ozone in the UTLS is a greenhouse gas and has radiative impacts at the surface, including changes in the surface temperatures and precipitation. This project aims at reducing uncertainty in trends through a homogenized meteorological coordinate system that incorporates vertical distance to the tropopause and horizontal distance to the sub-tropical jet to focus on the short- and long- term variability embedded in the NOAA ozonesonde records. This project will focus on resampling and analyses of 6 ozonesonde records (Boulder, Hilo, Trinidad Head, American Samoa, Fiji, and South Pole). The changes detected in the six NOAA ozonesonde records will be used for assessment of spatial and temporal variability in the long wave radiative effects that quantifies the UTLS greenhouse effect and its impact on changes in surface temperature.

Material injected into the upper atmosphere can be transported long distances and form complex, stratified structures. If a geo-engineering strategy that relies on injecting material into the upper atmosphere were to be performed, then probabilistic long-range forecasting of the transport and dispersion of the material would be needed to adequately plan releases. The transport and dispersion of emissions from volcanic eruptions are a useful natural laboratory to investigate these phenomena. This project will improve a method of estimating emissions from a volcanic eruption and devise a workflow which can provide timely emissions estimates to the modeling community. This will be particularly useful for eruptions with large umbrella clouds such as the Hunga Tonga volcano eruption in January of 2022.

As part of a broad approach of exploring optimal injection strategies, this project will study the extent to which MCB might be effective in delaying the breakup of the stratocumulus decks on the west coast of continents, thus significantly enhancing cloud fraction. If such an exercise were successful, and reliably so, significant albedo enhancement might be achieved.

The traditional way to evaluate MCB has been to study well-known case studies, or a handful of case studies to examine responses to aerosol perturbations. This project will take a much broader approach. It will use large ensembles of large eddy modeling simulations as a means of predicting the outcome of seeding efforts under a large range of naturally occurring atmospheric conditions. The team will build emulators (multi-dimensional interpolated surfaces) of the model output that mimic key radiative properties of the cloud fields such as cloud albedo and cloud fraction. These emulators will essentially act as kernel functions describing the sensitivity of a given cloud state to an aerosol injection. Then, by convolving this kernel function with different assumed perturbations, the expected outcome (degree of brightening) will be quantified. This will be a high-impact study that would provide guidance for operational decision making regarding the likelihood of a successful injection event.

Important unknowns in the assessment of the potential efficacy of MCB are the frequency of occurrence of susceptible cloud states, their areal fraction, and seasonable variability. Satellite-based remote sensing provides an opportunity to assess these susceptibilities globally, while ERA-5 reanalysis provides the meteorological context. This project will evaluate the global potential for MCB using such data. Key aspects of this work will be (i) evaluation of cloud liquid water and cloud fraction responses to aerosol perturbations, the sign and magnitude of which have the potential to significantly offset MCB efficacy; (ii) investigating ways in which one can separate between observed correlations between cloud amount and aerosol, and causal responses. New geostationary satellite data will be key to the latter.

This project will couple photo/OH/DMS/HPMTF chemistry into CSL's large eddy simulation or LES (SAM) to test hypotheses associated with the importance of cloud contact time, entrainment, and averaging scale in the partitioning of S(IV) and sulfate. Once this task is accomplished, the code can be tested in the future in a high resolution, 2-D Hadley cell (pole-to-pole) version of the same model to more broadly understand new particle formation in convective outflows. This project will provide simulations of observed cases to provide context and explanations for interpretation of the observations for the AEROMMA field mission.

This project will use and evaluate the Community Earth System Model Version 2 (CESM2) framework with a new implementation of a sectional aerosol model (CARMA) funded by ERB. We will evaluate the model performance on the stratospheric background sulfate aerosol, large volcanic eruptions (such as Pinatubo), and include a focus on the January 2022 Hunga Tonga-Hunga Ha'apai (HTHH) volcano eruption, which injected a relatively small amount of sulfur dioxide, but significantly more water into the stratosphere than previously seen in the modern satellite record. A second portion of this project is to simulate aerosol compositions in the Asian Tropopause Aerosol Layer, validating our simulations against many observations regarding optical properties, size distribution, and aerosol composition taken during the ACCLIP campaign. Our focus will be including the ammonium nitrate and ammonium sulfate aerosol, in addition to the sulfate, primary organics, secondary organics (SOA), sea salt, and dust, to investigate the contribution of primary and secondary aerosol to the Asian summer monsoon, new particle formation, and transport.

Stratospheric Aerosol Injection (SAI) is a proposed climate intervention method to reduce surface temperatures. The project will investigate multiple available climate model simulations using different SAI strategies and scenarios, with a focus on understanding uncertainties in the resulting changes in the large-scale stratospheric and tropospheric circulation, stratospheric ozone and surface climate. A number of different analyses are planned using existing experiments.

2023 ERB funding will support the operation and deployment of the NASA WB-57 high altitude research aircraft for Stratospheric Aerosol processes, Budget and Radiative Effects (SABRE) deployment to Houston, TX, and Fairbanks, AK. Support includes project flights, travel and logistics for the SABRE science team, and CSL personnel responsible for science flight planning and execution and the preparation, operation and data analysis for a number of CSL instruments in the SABRE payload. The goals of these flights are to sample aerosol gradients in the subtropical and midlatitude upper troposphere and lower stratosphere (from Houston) and characterize stratospheric aerosol composition, microphysics, radiative properties and impact on stratospheric chemistry at high northern latitudes (from Fairbanks). See SABRE for more information.

Perform Uncrewed Aerial System (UAS) flights for the measurement of vertical profiles of aerosol and cloud properties in the marine boundary layer. The overall goal is to further our understanding of the impacts of aerosols on direct radiative forcing and cloud properties in the marine boundary layer, a primary objective of NOAA's ERB Initiative. Marine stratus clouds along the west coast of the U.S. will be targeted during a 3 week deployment in the May to August 2023 time frame from a coastal site that offers ready access to dedicated flight space over the ocean. The anticipated outcome is a data set of aerosol and cloud properties that can be used by the ERB modeling community to address the ERB goal of improving our understanding of marine cloud properties and associated aerosol - cloud interactions.

This project will develop a methodology to quantify and map the past and future annual changes in the Earth's radiation budget using NOAA's state-of-the-art global climate models, and explain the contributions to the changing solar, longwave, and net radiation budget of the Earth system from anthropogenic and natural drivers, and consequent feedbacks. This understanding will contribute to determining the relative importance of the changing atmospheric constituents to the Earth's radiation budget and to the assessment of climate intervention strategies through changes in atmospheric composition.

The GML Ozone and Water Vapor (OZWV) division, in collaboration with the NOAA Chemical Sciences Laboratory (CSL), will continue to launch instrumented balloons every 3 weeks at Boulder (40°N), and quarterly at Hilo, Hawaii (20°N), Réunion Island (20°S) and Lauder, New Zealand (45°S). The balloons carry compact, lightweight instruments that measure vertical profiles of water vapor (WV), ozone (OZ), and aerosol number and size distribution from the surface to the middle stratosphere (~28 km). These measurements, made since June 2020, provide the data needed to characterize the background state and variability of radiatively important aerosols, WV and OZ in different regions of Earth's stratosphere. During this period of performance, we also plan to initiate a new quarterly sounding program at Barrow, Alaska (71°N), starting with balloon launches during the ERB-supported SABRE mission, to expand the latitudinal coverage of the B2SAP stratospheric composition measurements.

NOAA's new balloon-borne StratoCore sampler, adapted from the AirCore, is a low cost and highly accurate approach to measure a suite of long-lived stratospheric trace gases whose mole fractions are controlled by the rate of exchange of air between the troposphere, stratosphere and mesosphere. The work will leverage newly developed sample analysis techniques that retrieves routine seasonal mole fraction profiles of a suite of long-lived stratospheric species, enhancing NOAA's 10+ year record of AirCore trace gas profiles. StratoCore flights, coordinated with ozone, water vapor, and aerosol balloon flights will directly address the needs of the ERB Initiative to increase our instrumentation capabilities to conduct measurements of stratospheric gases and aerosols and to improve our modeling and predictive capabilities for stratospheric chemistry and dynamics. These new, stratospheric-focused observations, made seasonally by CIRES/GML and anchored by our growing time series of over a decade of AirCore trace gas measurements: a 53 year record of stratospheric ozone; a 40 year water vapor record, and a more recent record of stratospheric aerosols will help to establish a baseline state of stratospheric composition and transport for evaluating state-of-the-science models and will serve as a reference for changes in composition or transport in effect of potential climate intervention techniques.

The Global Climate Observing System (GCOS) Reference Upper Air Network (GRUAN) was established in 2008 to be an international network of sites making reference-quality measurements of essential climate variables above Earth's surface, designed to fill an important gap in the current global observing system. GRUAN measurements are providing long-term, high-quality climate data records from the upper troposphere into the lower stratosphere. These data are being used to determine trends, constrain and calibrate data from more spatially-comprehensive observing systems including satellites and current operational radiosonde networks, and provide important data for studying atmospheric processes. This project is geared to support the three US GRUAN sites in Boulder, CO; Beltsville, MD; and Lamont, OK; as well as the GRUAN station in Lauder, New Zealand.

This project has three primary focus areas for 2023 including: (a) Ongoing laboratory measurements of CaCO3 infrared radiative properties and the quantitative infrared absorption spectra of related minerals that may be formed in the stratosphere: Ca(OH)₂, CaCl₂, Ca(NO₃)₂, and CaSO₄. The results from these measurements will provide input to radiative transfer model calculations. (b) Investigation of the chemical transformation of CaCO₃ to other minerals from exposure to relevant stratospheric trace species, e.g. H₂O, HCl, HNO₃, N₂O₅, SO₂, H₂SO₄. (c) Experiments to measure the uptake of HCl and SO₂ on nano-particles of CaCO₃ under stratospherically relevant concentrations and conditions will be performed at the University of Crete.

This work supports two on-going projects that aim to address significant gaps in our understanding of how space travel may impact middle atmosphere climate. The first project will investigate climate effects from an increase in emissions from increases in satellite re-entry. The team will use a state-of-the-art sectional microphysical model to simulate multiple hypothetical aerosol size distributions and aerosol compositions. They will model the aerosol burden and potential radiative effects and finally look at the chemical effects. The second project investigates how new rocket fuel technology will impact climate. This study is a joint collaboration with Dr. Martin Ross of The Aerospace Corporation and the NASA Goddard Institute for Space Studies. The ultimate goal of this project is to evaluate how newly evolving methane rocket fuel technology may impact the middle atmosphere.

For the SABRE mission in 2023 the team will provide forecasting and flight planning support in the field during February and March as well as post-mission analysis through trajectories and other meteorological products.

This project will evaluate the impacts of aerosols as implemented in shallow, congestus, and deep convective parameterizations as well as microphysics parameterizations. Results and evaluations ranging from global to high-resolution regional model simulations and simple to complex parameterizations will be compared to observations during intensive field campaigns. Our experiments will primarily utilize WRF-Chem as embedded in the experimental Rapid-Refresh Model coupled to chemistry (RAP-Chem), which provides high-resolution CAM runs with complex physics/chemistry. For our more simplistic approaches, we will also utilize GEFS-Aerosols, an ensemble member of the GEFS Forecasting System as well as the Unified Forecast System (UFS).