(questions on telecomm data for climate)
the record-breaking cold winter of 2013-2014 across the midwest u. s. was associated with which of the following?
a.
easterly qbo
b.
positive tnh
c.
negative pna
d.
positive nao

C) Negative PNA

Explanation: PNA refers to the Pacific-North American tele-connection pattern which is responsible for the variations occurring in the atmospheric pressure and thus changing the atmospheric circulation. The natural variation in the climate can be in positive or negative phase .

The winter in 2013-2014 across Midwest US was due to negative PNA  because there was higher than average atmospheric pressure off the coast of Northern America. Thus option(c) is the correct answer.