This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 640276.
G2.12 Lack of rigorous pure rotational Raman temperature lidar error budget availability limits utility for applications such as satellite characterisation
Submitted by Anna Mikalsen on 12 June, 2017 - 10:41
Gap abstract:
Temperature lidars provide important information for trend detection in the middle atmosphere (connected to trends in the ozone layer). These are measured using lidar systems that often also measure the ozone layer. The lidar technique to measure temperature is sensitive to the presence of aerosol, which is an important contribution to the error budget. In addition, lidar techniques exist to measure temperature profiles in the troposphere using the pure-rotational Raman (PRR) technique that can be used in the presence of aerosol. For temperature measurements in the presence of aerosols using the PRR technique, a rigorous error budget needs to be established to improve their utility for applications such as satellite characterisation.
Part I Gap description
Primary gap type:
- Knowledge of uncertainty budget and calibration
ECVs impacted:
- Temperature
User category/Application area impacted:
- Operational services and service development (meteorological services, environmental services, Copernicus Climate Change Service (C3S) and Atmospheric Monitoring Service (CAMS), operational data assimilation development, etc.)
- Climate research (research groups working on development, validation and improvement of ECV Climate Data Records)
Non-satellite instrument techniques involved:
- Lidar
Detailed description:
Temperature lidars provide important information for trend detection in the middle atmosphere (connected to trends in the ozone layer). The temperature profiles in the middle atmosphere (12- 80 km altitude) are measured using lidar systems that often also measure the ozone layer. The temperature measurements are done using the Rayleigh-Mie technique. This lidar technique to measure temperature is sensitive to the presence of aerosol, which is an important contribution to the error budget. An additional lidar technique exists to measure temperature profile (in the troposphere) using the pure-rotational Raman technique (PRR) that can be used in the presence of aerosol. However, presently a metrologically traceable processing is unavailable for such measurements. Hence, for temperature measurements in the presence of aerosols using the PRR lidar technique, a rigorous error budget needs to be established to improve their utility for applications such as satellite characterization.
Operational space missions or space instruments impacted:
- Independent of specific space mission or space instruments
Validation aspects addressed:
- Time series and trends
- Auxiliary parameters (clouds, lightpath, surface albedo, emissivity)
Gap status after GAIA-CLIM:
- After GAIA-CLIM this gap remains unaddressed
Part II Benefits to resolution and risks to non-resolution
| Identified benefit | User category/Application area benefitted | Probability of benefit being realised | Impacts |
|---|---|---|---|
A traceable error budget for PRR temperature lidar will become available in addition to the existing RM temperature lidar used for the establishment of time series |
|
| Better climate records will become available. |
A traceable error PRR lidar budget will become available for the comparison to other techniques for temperature profile measurements. |
|
| Redundancy in time series will improve confidence in data records. |
PRR lidar error budgets will become available for users of data as auxiliary input. |
|
| Improved uncertainty budgets for products relying on auxiliary input from lidar temperature profiles. |
| Identified risk | User category/Application area at risk | Probability of risk being realised | Impacts |
|---|---|---|---|
Lack of rigorous temperature PRR lidar error budget availability |
|
| Reduced level of traceability of temperature lidar measurements leading to ambiguity in subsequent applications such as satellite Cal/Val. |
Part III Gap remedies
Gap remedies:
Remedy 1: Create a fully traceable reference-quality temperature lidar product
Primary gap remedy type:
Research
Secondary gap remedy type:
Technical
Deployment
Education/Training
Proposed remedy description:
The existing traceability chain for temperature lidar measurements will need to be expanded with the necessary elements for the temperature measurements with the pure rotational Raman Lidar technique. The chain will describe all the processing steps in the PRR temperature lidar measurement system. Robust estimation of uncertainties shall be undertaken that appropriately codifies the knowledge of each step and its resultant uncertainty. These uncertainties shall be used to derive an error budget calculation scheme which will be compiled. It shall be accompanied by detailed documentation of the measurement technique, the instrumental aspects, the processing steps and auxiliary input to the algorithms. These results shall be published via the peer reviewed literature. Processing shall be enacted such that products meeting the detailed procedures are available for end-users.
Relevance:
The issue is highly relevant for any application that uses ground based temperature lidar data as input or reference. In particular, to detect temperature trends in the middle atmosphere and aerosol-cloud-humidity interactions.
Measurable outcome of success:
Established (published in peer reviewed journal) error budget calculation scheme that includes detailed documentation of the measurement technique, the instrumental aspects, the processing steps and auxiliary input to the algorithms.
Expected viability for the outcome of success:
- High
Scale of work:
- Consortium
Time bound to remedy:
- Less than 3 years
Indicative cost estimate (investment):
- Low cost (< 1 million)
Indicative cost estimate (exploitation):
- No
Potential actors:
- EU H2020 funding
- Copernicus funding
- National funding agencies
- National Meteorological Services
- WMO
- ESA, EUMETSAT or other space agency