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banded structureIn radar, the arrangement of precipitation echoes in the form of long lines or bands.
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bandpass filterA digital, electrical, or mechanical system designed to attenuate all signals outside a specified frequency band, while passing signals within this band relatively unchanged.
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bandwidth1. In general, a range of frequencies specified by the number of hertz contained within the band or by the upper and lower limiting frequencies. 2. The range of frequencies that a device is capable of generating, handling, or accommodating; usually the range in which the response is within 3 dB of the maximum response. For example, the bandwidth of a modulated signal or of a bandpass filter is commonly defined by the frequencies at which the power spectral density is 3 dB (or a factor of 2) less than that within the band. 3. The amount of frequency space occupied by a signal and required for effective transfer of information by the signal. In data transmission, the greater the bandwidth, the greater the capacity to transmit data bits.
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bank storageWater absorbed and stored by the soil pores of the bed and banks of a stream, lake, or reservoir during higher stage periods and returned, fully or partially, to the water body as the water stage falls.
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bank1. The sloping margin of a stream or river that confines flow to the natural channel during normal stages. The top of this channel margin may be exceeded during overbank flood flows. 2. A steep slope or face, usually developed in unconsolidated material such as sand or gravel. 3. A shallow area in the sea or other water body, consisting of shifting sediment, and designated by a qualifying word, such as “gravel bank.”
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banner cloud(Also called cloud banner.) A cloud plume often observed to extend downwind from isolated, sharp, often pyramid-shaped mountain peaks, even on otherwise cloud-free days. The Matterhorn and Mount Everest are two notable peaks where banner clouds have been frequently observed.The physics of the formation of such clouds is not completely understood. The aerodynamics of the flow around the peak produces flow separation and dynamically induced pressure reductions to the lee of the mountain peaks. The magnitude of the leeside pressure deficits increases with height to a maximum near the top of the peak, producing an upslope pressure gradient and upslope flow along the lee slope of the mountain. When the air near the base of the mountain is sufficiently moist, it ascends in the upslope flow, condenses, and forms a triangular- shaped cloud, the banner cloud, to the lee of the peak. Because of its unusual shape and location, this cloud strongly resembles snow blowing off the peak (snow banner), and it is often difficult to tell the difference.
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