NOAA RESEARCH • EARTH SYSTEM RESEARCH LABORATORY • GLOBAL SYSTEMS DIVISION Evaluating the impact of Global Hawk observations to HWRF forecasts Author: James Taylor 1, 2, , Altug Aksoy 3 , Lidia Cucurull 1 1 NOAA ESRL/GSD, Boulder, CO; 2 CSU/CIRA, Fort Collins, CO; 3 Cooperative Institute for Marine and Atmospheric Studies, University of Miami, Miami, FL James Taylor, 303-497-5389, [email protected] http://www.esrl.noaa.gov/gsd/gosa / 1. Objective This project is motivated to understand the impact of observations from the Global Hawk Unmanned Aircraft System to forecasts of Atlantic tropical cyclones using the operational 2015 HWRF model. This research is a key component of the SHOUT project (Sensing Hazards with Operational Unmanned Systems) which aims to evaluate and test how targeted observations from aircraft over oceanic regions could improve model forecast of high impact events including tropical cyclones and winter storms. 2. Hurricane Matthew Flight Campaign 2016 Global Hawk completed 3 flights in and around Hurricane Matthew to observe both the inner and outer storm environment on 5 th ,7 th ,9 th October 2016. Here, the results of an Observation System Experiment (OSE) study is presented, where forecasts of Matthew are performed using HWRF for: NASA Global Hawk AVAPS The Advanced Vertical Atmospheric Profiling System is capable of deploying up to 88 dropsondes at altitudes up to 65,000ft, over a 28 hour flight time, providing high vertical resolution measurements of temperature, pressure, humidity and winds HAMSR The High Altitude MMIC Sounding Radiometer is a microwave temperature and humidity sounding instrument 3. Impact to HWRF track and intensity forecasts Figure 3 shows averaged track and intensity errors (compared to NHC tropical cyclone reports) from DROPS and CTL forecasts for cycles where GH dropsondes/HAMSR were available. DROPS and HAMSR both reduce track error compared to CTL after approx. 2 days into the forecast (Fig 3a), with the former producing the better performance and an improvement in track forecast of approx. 30% (Fig3b). The impact to intensity errors (10m max. wind speed and MSLP – Figs 3C-F) show more mixed results but with indications that both DROPS and HAMSR may lead to an improvement in intensity forecasts at longer lead times. HAMSR forecasts in particular showed good improvement in MSLP forecasts during this forecast period (Fig 3C-D). -ve +ve -ve +ve -ve +ve Number of Observations Assimilated HWRF domain d02 d03 Temperature ≈158,000 0 Humidity ≈158,000 0 Number of Observations Assimilated HWRF domain d02 d03 Temperature ≈170,000 ≈300,000 Humidity ≈170,000 ≈300,000 HAMSR Retrievals Map Matthew 14L 2016 Dropsondes Launch Locations Matthew 14L 2016 5 th Oct 12z Cycle 5 th Oct 18z Cycle 7 th Oct 12z Cycle Cat 1 Cat 2 Cat 1 Cat 4 Life Cycle of Matthew 14L 2016 Cycles with GH/HAMSR Figure 3: Track and intensity error statistics from CTL, DROPS and HAMSR forecasts, averaged at each forecast lead time over cycles where GH observations were available. National Hurricane Center Tropical Cyclone reports were used for verification of forecast metrics Figure 1: Maps showing flight paths (dashed line), dropsonde launch locations (blue circles), NHC observed track (line) and storm center (black star) for the 5 th , 7 th and 9 th flights. The grey boxes show the extent of HWRF domains d02 (6km resolution - light grey) and d03 (2km resolution - grey) where the data assimilation is performed. Figure 2: Maps showing location of HAMSR retrievals for the 10/05 12z and 18z cycles (purple squares), NHC observed track (line), storm center (star) and HWRF domains d02 and d03. 5 th Oct 18z Cycle 5 th Oct 12z Cycle # of Observations Assimilated HWRF domain d02 d03 T, UV ≈520 0 Humidity ≈300 0 # of Observations Assimilated HWRF domain d02 d03 T, UV ≈1350 ≈800 Humidity ≈830 ≈500 # of Observations Assimilated HWRF domain d02 d03 T, UV ≈1360 ≈2080 Humidity ≈990 ≈1170 1) CTL – Default 2015 Operational Setting 2) DROPS – CTL + Assimilation of Global Hawk Dropsondes 3) HAMSR – CTL + Assimilation of HAMSR Retrievals 4. Rainfall Impacts Comparisons of the accumulated rainfall totals from the 10/05 18z forecasts to observed rainfall totals (ECMWF) revealed that the good improvement to the track forecast from DROPS over CTL led to improvements in the forecast of accumulated rainfall over southeast corner of US, including North and South Carolina, which received some of the highest recorded amounts. Figure 4: Forecast along-track accumulated rainfall totals (mm) from CTL (left), DROPS (middle) from forecasts initiated on 5 th October 12z and observed rainfall totals taken from ??. 5. Structure and Analysis Humidity Analysis Increment Figure 8: Top row: Azimuthally averaged radial wind for CTL, DROPS, HAMSR for 10/05 18z cycle. Bottom row: Surface wind at analysis time for 10/05 18z. Figure 6: Average temperature and humidity increments at analysis time for 10/05 18z cycle as function of distance from center of storm Temperature Analysis Increment HAMSR DROPS CTL DROPS HAMSR CTL Averaged increments of temperature and humidity show a general increase in temperature and moistening of the PBL over the outer storm environment as a direct impact from the assimilation of the dropsondes (Fig 6). Oher key differences of the analysis include stronger mid-level radial wind field from HAMSR compared to DROPS and CTL
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NOAA RESEARCH • EARTH SYSTEM RESEARCH LABORATORY • GLOBAL SYSTEMS DIVISION
Evaluating the impact of Global Hawk observations to HWRF forecastsAuthor: James Taylor1, 2,, Altug Aksoy3, Lidia Cucurull1
1NOAA ESRL/GSD, Boulder, CO; 2CSU/CIRA, Fort Collins, CO; 3Cooperative Institute for Marine and Atmospheric Studies, University of Miami, Miami, FL
James Taylor, 303-497-5389, [email protected]
http://www.esrl.noaa.gov/gsd/gosa/
1. ObjectiveThis project is motivated to understand the impact of observationsfrom the Global Hawk Unmanned Aircraft System to forecasts ofAtlantic tropical cyclones using the operational 2015 HWRF model.This research is a key component of the SHOUT project (SensingHazards with Operational Unmanned Systems) which aims toevaluate and test how targeted observations from aircraft overoceanic regions could improve model forecast of high impactevents including tropical cyclones and winter storms.
2. Hurricane Matthew Flight Campaign 2016
Global Hawk completed 3 flights in and around Hurricane Matthew toobserve both the inner and outer storm environment on 5th, 7th, 9th
October 2016. Here, the results of an Observation System Experiment(OSE) study is presented, where forecasts of Matthew are performed usingHWRF for:
NASA Global Hawk
AVAPS
The Advanced Vertical AtmosphericProfiling System is capable of deployingup to 88 dropsondes at altitudes up to65,000ft, over a 28 hour flight time,providing high vertical resolutionmeasurements of temperature,pressure, humidity and winds
HAMSR
The High Altitude MMICSounding Radiometer is amicrowave temperatureand humidity soundinginstrument
3. Impact to HWRF track and intensity forecasts
Figure 3 shows averaged track and intensity errors (compared to NHCtropical cyclone reports) from DROPS and CTL forecasts for cycles whereGH dropsondes/HAMSR were available. DROPS and HAMSR both reducetrack error compared to CTL after approx. 2 days into the forecast (Fig 3a),with the former producing the better performance and an improvementin track forecast of approx. 30% (Fig3b). The impact to intensity errors(10m max. wind speed and MSLP – Figs 3C-F) show more mixed resultsbut with indications that both DROPS and HAMSR may lead to animprovement in intensity forecasts at longer lead times. HAMSR forecastsin particular showed good improvement in MSLP forecasts during thisforecast period (Fig 3C-D).
-ve
+ve
-ve
+ve
-ve
+ve
Number of Observations Assimilated
HWRF domain d02 d03
Temperature ≈158,000 0
Humidity ≈158,000 0
Number of Observations Assimilated
HWRF domain d02 d03
Temperature ≈170,000 ≈300,000
Humidity ≈170,000 ≈300,000
HAMSR Retrievals Map Matthew 14L 2016
Dropsondes Launch Locations Matthew 14L 2016
5th Oct 12z Cycle 5th Oct 18z Cycle 7th Oct 12z Cycle
Cat 1
Cat 2
Cat 1
Cat 4
Life Cycle of Matthew 14L 2016
Cycles with GH/HAMSR
Figure 3: Track and intensity error statistics from CTL, DROPS and HAMSR forecasts, averaged at
each forecast lead time over cycles where GH observations were available. National Hurricane
Center Tropical Cyclone reports were used for verification of forecast metrics
Figure 1: Maps showing flight paths (dashed line), dropsonde launch locations (blue circles),
NHC observed track (line) and storm center (black star) for the 5th, 7th and 9th flights. The grey
boxes show the extent of HWRF domains d02 (6km resolution - light grey) and d03 (2km
resolution - grey) where the data assimilation is performed.
Figure 2: Maps showing location of HAMSR retrievals for the 10/05 12z and 18z cycles (purple
squares), NHC observed track (line), storm center (star) and HWRF domains d02 and d03.
5th Oct 18z Cycle5th Oct 12z Cycle
# of Observations Assimilated
HWRF domain d02 d03
T, UV ≈520 0
Humidity ≈300 0
# of Observations Assimilated
HWRF domain d02 d03
T, UV ≈1350 ≈800
Humidity ≈830 ≈500
# of Observations Assimilated
HWRF domain d02 d03
T, UV ≈1360 ≈2080
Humidity ≈990 ≈1170
1) CTL – Default 2015 Operational Setting
2) DROPS – CTL + Assimilation of GlobalHawk Dropsondes
3) HAMSR – CTL + Assimilation of HAMSRRetrievals
4. Rainfall ImpactsComparisons of the accumulated rainfall totals from the 10/05 18zforecasts to observed rainfall totals (ECMWF) revealed that thegood improvement to the track forecast from DROPS over CTL ledto improvements in the forecast of accumulated rainfall oversoutheast corner of US, including North and South Carolina, whichreceived some of the highest recorded amounts.
Figure 4: Forecast along-track accumulated rainfall totals (mm) from CTL (left), DROPS (middle)
from forecasts initiated on 5th October 12z and observed rainfall totals taken from ??.
5. Structure and Analysis
Humidity Analysis
Increment
Figure 8: Top row: Azimuthally averaged radial wind for CTL, DROPS, HAMSR for 10/05 18z
cycle. Bottom row: Surface wind at analysis time for 10/05 18z.
Figure 6: Average
temperature and humidity
increments at analysis time
for 10/05 18z cycle as
function of distance from
center of storm
Temperature Analysis
Increment
HAMSRDROPSCTL
DROPS HAMSRCTL
Averaged incrementsof temperature andhumidity show ageneral increase intemperature andmoistening of the PBLover the outer stormenvironment as a directimpact from theassimilation of thedropsondes (Fig 6).Oher key differences ofthe analysis includestronger mid-levelradial wind field fromHAMSR compared toDROPS and CTL
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