Long-term sea-level projections with two versions of a global climate model of intermediate complexity and the corresponding changes in the Earth's gravity field

Approximate estimations of future climate change can be produced by implementing numerical global climate models. In this study, versions 2.6 and 2.7 of the University of Victoria Earth System Climate Model (ESCM) were employed. Compared to other climatic projections, the novelty of this study consists in a significant extension of the projection period to the time-scale of 4200 years, and in comparisons of the results obtained with two sequential versions 2.6 and 2.7 of ESCM. Version 2.6 of ESCM couples the atmospheric, oceanic and ice processes. Version 2.7 of ESCM accounts for solar and ice-sheet forcing, as well as coupling land-vegetation-atmosphere-ocean carbon, and allows inclusion of ocean biology and dynamic vegetation modules. Our comparison exhibits essential quantitative and, moreover, qualitative differences in the parameters under consideration, which are surface air temperature, sea-ice and snow volumes, and surface pressure in a column of water averaged globally.The observed differences are attributed to the biological blocks added to ESCM version 2.7, changed numerics and explicit ice-sheet forcing. Furthermore, the non-steric sea-level change has been used to model corresponding gravity field changes (here in terms of geoid height) by evaluating Newton's volume integral and study the differences between the two software versions under consideration. In line with the model results, the estimated geoid height changes also exhibit a significant difference between the experiments' outcomes

Integrating new sea-level scenarios into coastal risk and adaptation assessments: An on-going process

The release of new and updated sea-level rise information, such as from the Intergovernmental Panel on Climate Change (IPCC) Assessment Reports, needs to be better anticipated in coastal risk and adaptation assessments. This requires risk and adaptation assessments to be regularly reviewed and updated as needed, reflecting the new information but retaining useful information from earlier assessments. In this paper, updated guidance on the types of sea-level rise information available is presented, including for sea-level extremes. An inter-comparison of the evolution of the headline projected ranges across all the IPCC reports show an increase from the Fourth and Fifth assessments to the most recent ‘Special Report on the Ocean and Cryosphere in a Changing Climate’ assessment. Later IPCC reports have begun to highlight the importance of potential high-end sea-level response, mainly reflecting uncertainties in the Greenland/Antarctic ice sheet components, and how this might be considered in scenarios. The methods that are developed here are practical and consider coastal risk assessment, adaptation planning and long-term decision making to be an ongoing process and ensure that despite the large uncertainties pragmatic adaptation decisions can be made. It is concluded that new sea-level information should not be seen as an automatic reason for abandoning existing assessments, but as an opportunity to review (i) the assessment’s robustness in the light of new science, and (ii) the utility of proactive adaptation and planning strategies, especially over the more uncertain longer-term

COBE's search for structure in the Big Bang

The launch of Cosmic Background Explorer (COBE) and the definition of Earth Observing System (EOS) are two of the major events at NASA-Goddard. The three experiments contained in COBE (Differential Microwave Radiometer (DMR), Far Infrared Absolute Spectrophotometer (FIRAS), and Diffuse Infrared Background Experiment (DIRBE)) are very important in measuring the big bang. DMR measures the isotropy of the cosmic background (direction of the radiation). FIRAS looks at the spectrum over the whole sky, searching for deviations, and DIRBE operates in the infrared part of the spectrum gathering evidence of the earliest galaxy formation. By special techniques, the radiation coming from the solar system will be distinguished from that of extragalactic origin. Unique graphics will be used to represent the temperature of the emitting material. A cosmic event will be modeled of such importance that it will affect cosmological theory for generations to come. EOS will monitor changes in the Earth's geophysics during a whole solar color cycle

Towards a comprehensive assessment of exposure to sea-level rise at continental scale

Coastal areas are increasingly at risk from coastal hazards due to sea-level rise (SLR), which will accelerate in the 21st century driven by anthropogenic climate change. Future coastal risks are not only driven by the amount of SLR, but also by a high concentration of population and assets in locations potentially exposed to SLR-related hazards. The uncertainty related to future SLR and socioeconomic development can be explored with the SSP-RCP scenario framework, which consists of physical scenarios (RCPs – Representative Concentration Pathways) and socioeconomic scenarios (SSPs – Shared Socioeconomic Pathways), and is increasingly used in coastal risk assessments at continental to global scales. Thus far, such assessments have primarily focused on characterizing future changes in SLR-related hazards in a spatially explicit manner, while research on the spatial representation of variables to characterize exposure (e.g. population, assets, infrastructure) to those hazards has been limited, in particular with regard to exploring plausible future changes under the SSPs. Previous work that has characterized exposure spatially has used global-scale data, modeling approaches, and scenario assumptions when assessing coastal risks at continental scale. Therefore, this thesis advances the spatial representation of exposure to SLR-related hazards at continental scale to facilitate assessment of future coastal risks in an integrated manner. It focuses on two exposure variables, i.e. population and cultural assets, using the Mediterranean region as a study area. First, the global-scale SSP narratives are extended to the Mediterranean region, by including regional drivers of socioeconomic development, additionally differentiating northern versus southern and eastern countries of the region. The extended narratives are interpreted to develop spatial population projections for each SSP until 2100, accounting for the uncertainty related to future rural-urban and inland-coastal migration. Results show that the population potentially exposed to SLR-related hazards ranges from 34.1 million (SSP1) to 96.2 million (SSP3) in 2100, with marked differences across the Mediterranean. Comparison of these results with results based on the global SSPs shows a deviation of as much as 15% in the exposed population (SSP1), thereby spanning a wider range of uncertainty regarding population exposure. As this approach does not account for urban sprawl, a gravity-based modeling approach is developed, which allows for modeling urban sprawl as well as rural-urban and inland-coastal migration. The spatial population projections produced with this approach result in 51.3 million (SSP4) to 107.8 million (SSP3) people potentially exposed to SLR-related hazards in 2100. The results of the two approaches differ substantially, thereby stressing the need to consider the strengths and weaknesses of both approaches in future work. For more comprehensive coastal risk assessments, additional exposure variables need to be considered. Therefore, a spatial database of cultural assets, an exposure variable not commonly analyzed due to a lack of high-resolution spatial data, is assembled by producing spatial representations (i.e. polygons) of 49 UNESCO World Heritage Sites (WHS) located in low-lying coastal areas of the Mediterranean. A first application of the database in a continental-scale assessment shows that, already under current conditions, 75% and 85% of the WHS are at risk from coastal flooding and erosion, respectively. Both risks will increase until 2100, depending on the SLR scenario considered, with considerable differences between WHS and across the Mediterranean basin due to spatially varying characteristics of both risks. The results show that awareness regarding SLR-related risks posed to WHS is low and that adaptation is urgently needed to preserve WHS in the future. This thesis offers an important contribution to characterizing exposure to SLR-related hazards at continental scale, thereby facilitating the integrated assessment of coastal risks, accounting for future uncertainties in physical as well as socioeconomic processes. The results of this thesis stress the importance to explore different migration processes in spatial population projections; characterize additional exposure variables not commonly analyzed; and account for regional characteristics when assessing coastal risks at continental scale. Future work can extend the developed data and modeling approaches and can contribute to harmonizing data and modeling approaches that have gradually increased in recent years, to further advance coastal risk assessments at continental scale

Solid Earth science in the 1990s. Volume 3: Measurement techniques and technology

Reports are contained from the NASA Workshop on Solid Earth Science in the 1990s. The techniques and technologies needed to address the program objectives are discussed. The Measurement Technique and Technology Panel identified (1) candidate measurement systems for each of the measurements required for the Solid Earth Science Program that would fall under the NASA purview; (2) the capabilities and limitations of each technique; and (3) the developments necessary for each technique to meet the science panel requirements. In nearly all cases, current technology or a development path with existing technology was identified as capable of meeting the requirements of the science panels. These technologies and development paths are discussed

Modeling the Earth system in the Mission to Planet Earth era

A broad overview is made of global earth system modeling in the Mission to Planet Earth (MTPE) era for the multidisciplinary audience encompassed by the Global Change Research Program (GCRP). Time scales of global system fluctuation and change are described in Section 2. Section 3 provides a rubric for modeling the global earth system, as presently understood. The ability of models to predict the future state of the global earth system and the extent to which their predictions are reliable are covered in Sections 4 and 5. The 'engineering' use of global system models (and predictions) is covered in Section 6. Section 7 covers aspects of an increasing need for improved transform algorithms and better methods to assimilate this information into global models. Future monitoring and data requirements are detailed in Section 8. Section 9 covers the NASA-initiated concept 'Mission to Planet Earth,' which employs space and ground based measurement systems to provide the scientific basis for understanding global change. Section 10 concludes this review with general remarks concerning the state of global system modeling and observing technology and the need for future research

Comparison of sea-ice freeboard distributions from aircraft data and cryosat-2

The only remote sensing technique capable of obtain- ing sea-ice thickness on basin-scale are satellite altime- ter missions, such as the 2010 launched CryoSat-2. It is equipped with a Ku-Band radar altimeter, which mea- sures the height of the ice surface above the sea level. This method requires highly accurate range measure- ments. During the CryoSat Validation Experiment (Cry- oVEx) 2011 in the Lincoln Sea, Cryosat-2 underpasses were accomplished with two aircraft, which carried an airborne laser-scanner, a radar altimeter and an electro- magnetic induction device for direct sea-ice thickness re- trieval. Both aircraft flew in close formation at the same time of a CryoSat-2 overpass. This is a study about the comparison of the sea-ice freeboard and thickness dis- tribution of airborne validation and CryoSat-2 measure- ments within the multi-year sea-ice region of the Lincoln Sea in spring, with respect to the penetration of the Ku- Band signal into the snow

NASA earth science and applications division: The program and plans for FY 1988-1989-1990

Described here are the Division's research goals, priorities and emphases for the next several years and an outline of longer term plans. Included are highlights of recent accomplishments, current activities in FY 1988, research emphases in FY 1989, and longer term future plans. Data and information systems, the Geodynamics Program, the Land Processes Program, the Oceanic Processes Program, the Atmospheric Dynamics and Radiation Program, the Atmospheric Chemistry Program, and space flight programs are among the topic covered