Altimetry for the future: Building on 25 years of progress

In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and more recently, in 2018, in Ponta Delgada, Portugal, 25 Years of Progress in Radar Altimetry. On this latter occasion it was decided to collect contributions of scientists, engineers and managers involved in the worldwide altimetry community to depict the state of altimetry and propose recommendations for the altimetry of the future. This paper summarizes contributions and recommendations that were collected and provides guidance for future mission design, research activities, and sustainable operational radar altimetry data exploitation. Recommendations provided are fundamental for optimizing further scientific and operational advances of oceanographic observations by altimetry, including requirements for spatial and temporal resolution of altimetric measurements, their accuracy and continuity. There are also new challenges and new openings mentioned in the paper that are particularly crucial for observations at higher latitudes, for coastal oceanography, for cryospheric studies and for hydrology. The paper starts with a general introduction followed by a section on Earth System Science including Ocean Dynamics, Sea Level, the Coastal Ocean, Hydrology, the Cryosphere and Polar Oceans and the ‘‘Green” Ocean, extending the frontier from biogeochemistry to marine ecology. Applications are described in a subsequent section, which covers Operational Oceanography, Weather, Hurricane Wave and Wind Forecasting, Climate projection. Instruments’ development and satellite missions’ evolutions are described in a fourth section. A fifth section covers the key observations that altimeters provide and their potential complements, from other Earth observation measurements to in situ data. Section 6 identifies the data and methods and provides some accuracy and resolution requirements for the wet tropospheric correction, the orbit and other geodetic requirements, the Mean Sea Surface, Geoid and Mean Dynamic Topography, Calibration and Validation, data accuracy, data access and handling (including the DUACS system). Section 7 brings a transversal view on scales, integration, artificial intelligence, and capacity building (education and training). Section 8 reviews the programmatic issues followed by a conclusion

Altimetry for the future: building on 25 years of progress

In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and more recently, in 2018, in Ponta Delgada, Portugal, 25 Years of Progress in Radar Altimetry. On this latter occasion it was decided to collect contributions of scientists, engineers and managers involved in the worldwide altimetry community to depict the state of altimetry and propose recommendations for the altimetry of the future. This paper summarizes contributions and recommendations that were collected and provides guidance for future mission design, research activities, and sustainable operational radar altimetry data exploitation. Recommendations provided are fundamental for optimizing further scientific and operational advances of oceanographic observations by altimetry, including requirements for spatial and temporal resolution of altimetric measurements, their accuracy and continuity. There are also new challenges and new openings mentioned in the paper that are particularly crucial for observations at higher latitudes, for coastal oceanography, for cryospheric studies and for hydrology. The paper starts with a general introduction followed by a section on Earth System Science including Ocean Dynamics, Sea Level, the Coastal Ocean, Hydrology, the Cryosphere and Polar Oceans and the “Green” Ocean, extending the frontier from biogeochemistry to marine ecology. Applications are described in a subsequent section, which covers Operational Oceanography, Weather, Hurricane Wave and Wind Forecasting, Climate projection. Instruments’ development and satellite missions’ evolutions are described in a fourth section. A fifth section covers the key observations that altimeters provide and their potential complements, from other Earth observation measurements to in situ data. Section 6 identifies the data and methods and provides some accuracy and resolution requirements for the wet tropospheric correction, the orbit and other geodetic requirements, the Mean Sea Surface, Geoid and Mean Dynamic Topography, Calibration and Validation, data accuracy, data access and handling (including the DUACS system). Section 7 brings a transversal view on scales, integration, artificial intelligence, and capacity building (education and training). Section 8 reviews the programmatic issues followed by a conclusion

Design weight of armour stone considering the effect of extreme waves

In this study, waves with the heights higher than H-1/3 in an irregular wave train are called as extreme waves and defined with the help of extreme wave parameter, alpha(extreme). In order to see the effect of extreme waves on the design weight of armour stone, stability analysis is carried out based on the hydraulic model test results. The test results of high alpha(extreme) cases (HE) and low alpha(extreme) cases (LE) are compared with currently used van der Meer's formulae with permeability factor P = 0.4 and 0.45 and Hudson formula by using H-1/3 and H-1/10 in terms of the design weight of armour stone. As a result of the comparison, it is found that Hudson formula by using H-1/3 underestimates the necessary armour weight. Usage of H-1/10 instead of H-1/3 in Hudson formula doubles the weight which seems overestimated when Irribaren number is away from the transition zone in which both wave run-up and run-down forces become effective. However, it seems underestimated near the transition zone where experiment case HE gives higher armour weights. When the design weight of armour stone is calculated by van der Meer's formulae with P = 0.4, it may be necessary to increase the weight up to 30% in the case of high extreme waves. On the other hand, van der Meer's formulae may overestimate the weight 14% when the extreme waves are low

TFP growth in Turkey revisited: The effect of informal sector

In this paper, we aim to contribute to the growth literature by presenting evidence that the presence of an informal sector might significantly affect both the level as well as the course of the total factor productivity (TFP). To this end, we develop a framework where we can compare the TFP in Turkey generated by a one-sector benchmark model to the one originating from an extended model with the presence of formal and informal labor. Our results indicate that, over the course of 1950–2014, the TFP generated by the benchmark model generally underestimates the productivity of the formal sector and this underestimation is mainly observed and is widened after 1980. Moreover, we also find that the substitution between formal and informal labor significantly affects this underestimation

Left upper lobe atelectasis due to plastic bronchitis

Plastic bronchitis is a rare condition in children, characterized by expectoration of branching bronchial casts. It can cause atelectasis in the lung. Herein we reported a 4.5-year-old boy with left upper lobe atelectasis due to plastic bronchitis. Although his chest X-ray is specific for left upper left atelectasis, thoracic computerized tomography had been performed and was compatible with obliterated left upper lobe bronchus. Typical radiological appearance of the left upper lobe atelectasis is not well known by clinicians which results unnecessary further examinations such as computerized tomography which exposes high dose radiation. We want to emphasize the long-term side effects of radiation and avoid unnecessary examinations in children

Pterygopalatine Fossa: Not a Mystery!

The pterygopalatine fossa is an important anatomic crossroads that is connected with numerous intra-and extracranial spaces via foramina and fissures. Although this fossa is small, its central location in the skull base and its communications provide clinical, radiological, and anatomical significance. In this pictorial review, we aimed to describe the radiologic anatomy of the pterygopalatine fossa, as well as to give some pathologic examples to better understand this major conduit

MRI and CT findings of isolated intracranial Rosai-Dorfman disease in a child.

Isolated intracranial Rosai-Dorfman disease (RDD) is extremely rare in pediatric patients. We present the case of a 22-month-old boy whom had isolated intracranial RDD involvement. To our knowledge, a parieto-occipital regional involvement without a dural tail sign has not been previously documented. Also, the mass contained hyperintense central T1 foci, and hypointense T2 and gradient echo foci; which are helpful in the differential diagnosis from meningioma. The magnetic resonance and computed tomography imaging findings are discussed and the follow-up course is presented in this paper