Targeted in-situ observations improve hurricane intensity predictions, but not track predictions?
Abstract
The benefits of additional targeted dropsonde observations from the NASA Global Hawk Unmaned Aerial System on hurricane intensity and track predictions are examined for the 2016 Atlantic hurricane season. These observations were taken as part of the NOAA project "Sensing Hazards with Operational Unmanned Technology (SHOUT)". The effects are evaluated in the NCEP Global Ensemble Forecast System (GEFS) by comparing two sets of 10-day, 81-member ensemble forecasts that differ in their inclusion or exclusion of additional hurricane observations for preparing initial conditions. The 81 members are composed of one high-resolution (~0.23o) member plus 80 low-resolution (~0.70o) members. Including the additional observations is found to deepen the hurricane central pressure in the high-resolution forecasts, but does not improve the track forecast.
The possibility of using ensemble forecasts to generate probabilistic and flow-dependent hurricane track forecasts is also explored. The "cone" width of the track uncertainty is defined so that two-thirds of the tracks from the ensemble forecasts fall within the cone. Unlike the widely-used historical 5-year track cone, the flow-dependent track cone depends on both the forecast lead time and concurrent meteorological conditions. The cone width differences resulting from the inclusion and exclusion of additional hurricane observations can thus be used to quantify the impact of such observations in the probabilistic forecast sense. The additional observations are found to have a small effect on the spread of ensemble track forecasts.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMA196...03W
- Keywords:
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- 3314 Convective processes;
- ATMOSPHERIC PROCESSES;
- 3355 Regional modeling;
- ATMOSPHERIC PROCESSES;
- 1817 Extreme events;
- HYDROLOGY;
- 4313 Extreme events;
- NATURAL HAZARDS