Development of GRASP radiative transfer code for the retrieval of aerosol microphysics vertical-profiles from space measurements and its impact in ACE mission

Project Information

GRASP-ACE

Grant agreement ID: 778349

DOI

10.3030/778349

Project closed

EC signature date 22 November 2017

Start date 1 March 2018

End date 31 August 2023

Funded under

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Total cost

€ 877 500,00

EU contribution

€ 877 500,00

Coordinated by

UNIVERSIDAD DE GRANADA
Spain

Periodic Reporting for period 2 - GRASP-ACE (Development of GRASP radiative transfer code for the retrieval of aerosol microphysics vertical-profiles from space measurements and its impact in ACE mission)

Reporting period: 2020-03-01 to 2023-08-31

Summary of the context and overall objectives of the project

The focus of this project is on advancing in methodologies for atmospheric aerosols characterization. Actually, the Executive Summary of the 2013 IPCC's states that reducing the uncertainty in direct aerosol radiative forcing is a necessary step in reconciling estimates of radiative forcing and the equilibrium climate sensitivity of the Earth so that future predictions of surface temperature associated with climate change can be made with confidence. To that end, improved aerosol knowledge about vertically resolved measurements is essentia and particularly aerosol absorption characterization. Previous space missions (e.g. e.g. Terra, Aqua, POLDER, CALIPSO or CloudSat platforms) were not able to provide layer-resolved aerosol absorption. The NASA Aerosol-Cloud-Ecosystems (ACE) mission is 2007 Decadal Survey that addresses this problem. ACE was replaced by the Aerosol-Cloud-Convection-Precipitation (ACCP) mission following 2017 Decadal Survey and is already on phase of construction. ACCP includes multiwavelength lidar and polarimeter flying together but still there is no appropriate software for characterizing aerosol microphysical and optical properties from the space.

The main objective of this proposal is the development and implementation of the joint inversion in GRASP for space polarimeter + lidar instruments to retrieve independent and accurate vertical profiles of aerosol microphysical properties. Such an approach is critical for future space missions such as ACE and ACCP, and will allow aerosol microphysics vertical-profiles, particularly for absorption properties. To fulfill this objective we divide the goals in:
1. Study of capabilities of the joint inversion through new mathematical developments and sensitivity test analyses.
2. Evaluation of the GRASP joint inversion from field campaign data and their advantages over the classical stand-alone 3β+2α lidar inversion.
3. Exploring merging data of different satellite missions for implementing GRASP joint inversion.
4. Defining synergies in ground-based networks for the evaluation of aerosol microphysics satellite products.

The achievement of all these scientific objectives have permitted large advances in GRASP algorithm that have permitted the company GRASP-SAS to expand their business and growth. Also, all the achievements have permitted an advance in space sciences by delimiting the capabilities of the sensors and facilities synergies. Aerosol science have been also benefit by improving the retrieval capabilities of aerosol properties through GRASP algorithm.

All these research activities were carried out by the staff of the different institutions that formed the consortium created for the Marie Curie RISE call. The consortium was inter-sectorial and we implemented more than 85% of the secondments initially planned. The consortium overcome exceptional situations such as the COVID-19 pandemia or the war in Ukraine.

We organized an international workshop related to the project with the attendance of more of than 100 prestigious scientists. After that, the second GRASP summer school was organized with the attendance of international students.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

During this second period we carried out an extensive analyses of GRASP capabilities for retrieving aerosol microphysical properties vertically resolved using space sensors, particularly polarimetry plus lidar systems. The results are successful although it implies limitations in the parameters to retrieve due to the complexity of ill-posed problem. In particular, it has been found that limitations due to complexity of retrieving aerosol plus surface parameters can be solved if the GRASP multipixel approach is used. That approach can be applied to the combination POLDER + CALIPSO and has a great potential for the upcoming satellite missions that combine lidar + polarimetry. Exploitation of this new GRASP approach are done using ACEPOL field campaign data where HSRL-2 plus AirHARP measurements is available. On the other hand, we have also evaluated the combination of instrument for aerosol retrieval using surface remote sensing instrumentation, particularly in how to obtain continuous day-to-night properties combining sun/moon photometry with lidar. Several studies have been published in this sense, although more work need to be done in future project related to determining the sensitivity to errors in the input optical data and to the limitations in lidar measurements.

More than 20 peer-review publications were published as a result of the research activities, and we also attended to many international conferences. Of particular interest is the GRASP-ACE Workshop organized in Lille in Spring 2023 that was a great success.

Several dissemination activities were carried out by the consortium that included the participation of researchers in the European Research Night and visits to public middle/high schools. Also, we participated actively in activities for promoting women in science.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The development of a joint inversion in GRASP that combines multiwavelength polarimetry and lidar measurements suppose an achievement in aerosol sciences by permitting to retrieve aerosol microphysical properties vertically resolved from the space. This GRASP configuration was evaluated using airborne data acquired during the ACEPOL field campaign, which give more potential to the GRASP software. The analyses performed show that very complex and expensive systems based on HSRL are not required for daytime aerosol characterization, although they are extremely helpful in helping to retrieve surface parameters. Thus, we are providing new insight to the space business by providing new instrument capabilities needed for aerosol studies. This permit cheaper instruments that can ultimately make space missions happens. All these studies were aligned with the upcoming Aerosol-Clouds-Convection-Precipitation (ACCP) NASA mission that took the heritage of the previous Aerosol-Clouds-Ecosystems NASA mission. As a results of ACCP the Aerosol Observing System (AOS) was approved with a polarimetry and lidar planned to be implemented.

The activities performed during the project have permitted the company GRASP-SAS to growth exponentially both in terms of personnel and in their product application. Actually, GRASP is becoming the operational algorithm in many upcoming ESA/EUMESAT missions.

Group Picture of the Workshop Lille 2023

Picture of the professors participating in GRASP-ACE summer school 2023