The “ABC model”: a non-hydrostatic toy model for use in convective-scale data assimilation investigations

In developing methods for convective-scale data assimilation (DA) it is necessary to consider the full range of motions governed by the compressible Navier-Stokes equations (including non-hydrostatic and ageostrophic flow). These equations describe motion on a wide range of time-scales with non-linear coupling. For the purpose of developing new DA techniques that suit the convective-scale problem it is helpful to use so-called ‘toy models’ that are easy to run, and contain the same types of motion as the full equation set. Such a model needs to permit hydrostatic and geostrophic balance at large-scales, but to allow imbalance at small-scales, and in particular, it needs to exhibit intermittent convection-like behaviour. Existing ‘toy models’ are not always sufficient for investigating these issues. A simplified system of intermediate complexity derived from the Euler equations is presented, which supports dispersive gravity and acoustic modes. In this system the separation of time scales can be greatly reduced by changing the physical parameters. Unlike in existing toy models, this allows the acoustic modes to be treated explicitly, and hence inexpensively. In addition, the non-linear coupling induced by the equation of state is simplified. This means that the gravity and acoustic modes are less coupled than in conventional models. A vertical slice formulation is used which contains only dry dynamics. The model is shown to give physically reasonable results, and convective behaviour is generated by localised compressible effects. This model provides an affordable and flexible framework within which some of the complex issues of convective-scale DA can later be investigated. The model is called the “ABC model” after the three tunable parameters introduced: A (the pure gravity wave frequency), B (the modulation of the divergent term in the continuity equation), and C (defining the compressibility)

Ancient Egypt 1920 Part 1

Part 1 of the 1920 Ancient Egypt books. Contents include the return to research, Nile boats, the treasure of Antinoe, a mace head of Hierakonpolis, and an early portrait.https://knowledge.e.southern.edu/kweeks_coll/1010/thumbnail.jp

Ancient Egypt 1920 Part 2

Part 2 of the 1920 Ancient Egypt books. Contents include a Mentuhetep statue, varnishes in Theban tombs, the kings of Ethiopia, and Nile boats (continued).https://knowledge.e.southern.edu/kweeks_coll/1011/thumbnail.jp

Ancient Egypt 1915 Part 1

Part 1 of the 1915 Ancient Egypt books. Contents include birds in ancient Egyptian art, excavations at Saqqara, part of a Coptic sermon, and the metals in Egypt.https://knowledge.e.southern.edu/kweeks_coll/1001/thumbnail.jp

Ancient Egypt 1922 Part 2

Part 2 of the 1922 Ancient Egypt book. Contents include the British school in Egypt, the set rebellion, and Egyptian words in modern use.https://knowledge.e.southern.edu/kweeks_coll/1019/thumbnail.jp

Ancient Egypt 1921 Part 2

Part 2 of the 1921 Ancient Egypt books. Contents include the British school in Egypt, origins of some signs, borders of lotus and grapes, the head of a barbarian, the transmission of history, and a cartouche of Augustus.https://knowledge.e.southern.edu/kweeks_coll/1015/thumbnail.jp

LANDSAT TM image data quality analysis for energy-related applications

This project represents a no-cost agreement between National Aeronautic Space Administration Goddard Space Flight Center (NASA GSFC) and the Pacific Northwest Laboratory (PNL). PNL is a Department of Energy (DOE) national laboratory operted by Battelle Memorial Institute at its Pacific Northwest Laboratories in Richland, Washington. The objective of this investigation is to evaluate LANDSAT's thematic mapper (TM) data quality and utility characteristics from an energy research and technological perspective. Of main interest is the extent to which repetitive TM data might support DOE efforts relating to siting, developing, and monitoring energy-related facilities, and to basic geoscientific research. The investigation utilizes existing staff and facility capabilities, and ongoing programmatic activities at PNL and other DOE national laboratories to cooperatively assess the potential usefulness of the improved experimental TM data. The investigation involves: (1) both LANDSAT 4 and 5 TM data, (2) qualitative and quantitative use consideration, and 3) NASA P (corrected) and A (uncorrected) CCT analysis for a variety of sites of DOE interest. Initial results were presented at the LANDSAT Investigator's Workshops and at specialized LANDSAT TM sessions at various conferences

Ancient Egypt 1923 Part 2

Part 2 of the 1923 Ancient Egypt books. Contents include the tomb at Byblos, a tomb with Aramaic inscriptions, the British school at Qau, the magic skin, Apries and the possibility of royal blood, and obelisks at Pylon VII.https://knowledge.e.southern.edu/kweeks_coll/1023/thumbnail.jp

Ancient Egypt 1921 Part 1

Part 1 of the 1921 Ancient Egypt books. Contents include the alphabet in the XIIth dynasty, the Lahun caskets, burial rites of West Africa, a Negro captive, and Queen Tetisheri.https://knowledge.e.southern.edu/kweeks_coll/1014/thumbnail.jp

Ancient Egypt 1920 Part 4

Part 4 of the 1920 Ancient Egypt books. Contents include Coptic twists and plaits, the sphinxes of Tanis, Alexandrian world maps, passages of Aleppo Citadel, and Kheker friezes.https://knowledge.e.southern.edu/kweeks_coll/1013/thumbnail.jp