Nature Run Model (NR)

North Atlantic Hurricane Region Hybrid Coordinate Ocean Model (ATL-HYCOM)
Nature Run Model (NR)

The NR has been evaluated using a variety of available observations, such as from AVISO, GDEM climatology, GHRSST observations and historical drifter dataset. The NR demonstrates sufficient realism in terms of mean climatology.
Observations vs. NR

(a) SSH:
    The six year (2009-2014) mean of SSH from the free-run NR is compared to the mean field of SSH from AVISO Mean Dynamic Topography. Large-scale patters of the Gulf Stream and a subtropical gyre in the open Atlanic Ocean, the Loop Current in the Gulf of Mexico, the North Brazil Current along the northeastern coast of South America and continuation of nowthwad current in the Caribbean are similar in both the NR and the observations. Intensity and extending of the Gulf Stream, the Loop Current and the North Brazil Current are different; the observed Gulf Stream extends far eastward with intensified values of SSH while the extension part of the Gulf Stream is absent in the NR. A cyclonic pattern in the SW Gulf of Mexico and lower SSH patterns are in the NR as captured in the observed SSH. The NR simulates higer SSH than the AVISO SSH in Caribbean (Loop Current entering) and around the islands. Lack  of calibrating in-situ date in the area could be accountable for the observed SSH to have lower values.
(b) Surface Current:
     The six-year (2009-2014) means of Surface Current from the free-run NR is compared to the mean field of Surface Current from AVISO.
(c) SST:
    The six-year (2009-2014) mean of SST from the free-run NR compares to the mean SST from the Group for High Resolution Sea Surface Temperature (GHRSST). The warm-water carrier Gulf Stream and the thermal fronts across the North Atlantic are very visible in the NR as captured in the GJRSST mean climatolog. The simulated SST is warmer than the observed one in the western Caribbean while it is cooler in the south of Equater in open Atlantic (low termperature pool) and along the Brazilian coast.
Villy Kourafalou —
HeeSook Kang —