Coming to us from the University of Miami, Jennifer is a junior studying
Meteorology with a minor in Mathematics.
The Madden-Julian Oscillation (MJO) is an eastward moving oscillation of deep
convection and large-scale circulation occurring in the equatorial Indian and
western/central Pacific Oceans with a timescale of about 30-90 days. CSU's
superparameterized Community Atmosphere Model version 3.0 (SP-CAM) has a fairly
realistic MJO (Benedict and Randall 2009); therefore it is of interest to
compare its moisture cycle to that in the observed MJO. Understanding the
moisture cycle of the MJO may be key in understanding the MJO itself: for
example, in the "Discharge-Recharge Mechanism" of the MJO (Blade and Hartmann
1993), moisture builds up locally until it reaches a tipping point, causing
large-scale convection that in turn dries the air. The timescale of this cycle
determines the timescale of the MJO.
In this study, SP-CAM's MJO moisture cycle is compared to that of the observed
MJO. Observations include precipitable water and precipitation from the
Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI), and specific
humidity and zonal wind data from the NCEP-DOE Reanalysis 2 dataset.
In general, the SP-CAM's moisture cycle is more variable than the observed MJO
moisture cycle. During the active phase of the MJO, SP-CAM has more individual
peaks in precipitable water and a quicker recharge phase than the observations,
which show a slower, smoother progression. Plots of TMI precipitable water vs.
precipitation averaged from 5N to 10S show a clockwise progression with time,
implying higher precipitable water during the recharge phase. This trend is
less clear when averaged over 15N to 15S, and not as evident in the SP-CAM for
either latitudinal average. Additionally, cross-sections of specific humidity
anomalies show that the SP-CAM accumulation of moisture occurs earlier in the
MJO cycle than in observations, with more simultaneity at all levels, and for a
longer period of time. In some cases, SP-CAM also has negative specific humidity
anomalies at lower levels during the MJO, which is not consistent with
observations.
Jennifer's summer research poster,
Moisture Cycle of the Madden-Julian Oscillation: An Analysis of TRMM and SP-CAM Data, may be found here (2MB).
Outside of her climate studies, Jenny enjoys playing flute and piccolo for
marching band, Irish step dancing and fencing!
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